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  • 1. Allahverdiyeva, Yagut
    et al.
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Suorsa, Marjaana
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Vass, Imre
    Aro, Eva-Mari
    Insights into the function of PsbR protein in Arabidopsis thaliana2007In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1767, no 6, p. 677-685Article in journal (Refereed)
    Abstract [en]

    The functional state of the Photosystem (PS) II complex in Arabidopsis psbR T-DNA insertion mutant was studied. The DeltaPsbR thylakoids showed about 34% less oxygen evolution than WT, which correlates with the amounts of PSII estimated from Y(D)(ox) radical EPR signal. The increased time constant of the slow phase of flash fluorescence (FF)-relaxation and upshift in the peak position of the main TL-bands, both in the presence and in the absence of DCMU, confirmed that the S(2)Q(A)(-) and S(2)Q(B)(-) charge recombinations were stabilized in DeltaPsbR thylakoids. Furthermore, the higher amount of dark oxidized Cyt-b559 and the increased proportion of fluorescence, which did not decay during the 100s time span of the measurement thus indicating higher amount of Y(D)(+)Q(A)(-) recombination, pointed to the donor side modifications in DeltaPsbR. EPR measurements revealed that S(1)-to-S(2)-transition and S(2)-state multiline signal were not affected by mutation. The fast phase of the FF-relaxation in the absence of DCMU was significantly slowed down with concomitant decrease in the relative amplitude of this phase, indicating a modification in Q(A) to Q(B) electron transfer in DeltaPsbR thylakoids. It is concluded that the lack of the PsbR protein modifies both the donor and the acceptor side of the PSII complex.

  • 2.
    Anderlund, Magnus F.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Zheng, J.
    Ghiladi, Marten
    Kritikos, Mikael
    Riviere, Eric
    Sun, Licheng
    Girerd, Jean-Jacques
    Åkermark, Björn
    A new, dinuclear high spin manganese(III) complex with bridging phenoxy and methoxy groups. Structure and magnetic properties2006In: Inorganic Chemistry Communications, Vol. 9, no 12, p. 1195-1198Article in journal (Refereed)
  • 3.
    Berggren, G.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Photochemistry and Molecular Science, Molecular Biomimetics. Avdelningen för molekylär biomimetik.
    Anderlund, M.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Photochemistry and Molecular Science, Molecular Biomimetics. Avdelningen för molekylär biomimetik.
    Magnuson, A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Photochemistry and Molecular Science, Molecular Biomimetics. Avdelningen för molekylär biomimetik.
    Åkermark, B.
    Eriksson, L.
    Sodium [1,2-bis(2-methyl-2-oxopropanamido)-benzene](tetrahydrofuran) manganese(III) methanol solvate2005In: Acta Crystallographica Section E-Structure Reports Online, Vol. 61, p. M1169-Article in journal (Refereed)
  • 4.
    Berggren, Gustav
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Huang, Ping
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Eriksson, Lars
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Anderlund, Magnus F.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Thapper, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Synthesis and characterisation of low valent Mn-complexes as models for Mn-catalases2010In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 39, no 45, p. 11035-11044Article in journal (Refereed)
    Abstract [en]

    In this work we report the synthesis of two novel manganese complexes, [L1(3)Mn(6)(II)](ClO4)(6) (1 center dot(ClO4)(6)) and [L2Mn(2)(II)(mu-OAc)(mu-Cl)](ClO4)(2) (2 center dot(ClO4)(2)), where L1(2-) is the 2,2'-(1,3-phenylenebis(methylene))bis-((2-(bis(pyridin-2-ylmethyl)amino)ethyl)azanediyl)diacetic acid anion and L2 is N1,N1'-(1,3-phenylenebis(methylene))bis(N2,N2'-bis(pyridin-2-ylmethyl)ethane-1,2-diamine). The ligands Na(2)L1 and L2 are built on the same backbone, L2 only contains nitrogen donors, while two carboxylate arms have been introduced in Na(2)L1. The two complexes have been characterized by single-crystal X-ray diffraction, magnetic susceptibility, EPR spectroscopy, and electrochemistry. X-Ray crystallography revealed that 1 is a manganese(II) hexamer and 2 is a manganese(II) dimer featuring an unprecedented mono-mu-acetato, mono-mu-chlorido bridging motif. The ability of the complexes to catalyse H2O2 disproportionation, thereby acting as models for manganese catalases, has been investigated and compared to the activity of two other related manganese complexes. The introduction of carboxylate donors in the ligands, leading to increased denticity, resulted in a drop in H2O2 disproportionation activity.

  • 5.
    Borgström, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Shaikh, Nizamuddin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Johansson, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Anderlund, Magnus
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Åkerman, Björn
    Magnusson, Ann
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Light induced manganese oxidation and long-lived charge separation in a Mn2II,II-RuII(bpy)3-acceptor triad2005In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 127, no 49, p. 17504-17515Article in journal (Refereed)
    Abstract [en]

    The photoinduced electron-transfer reactions in a Mn2II,II-RuII-NDI triad (1) ([Mn2(bpmp)(OAc)2]+, bpmp = 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenolate and OAc = acetate, RuII = tris-bipyridine ruthenium(II), and NDI = naphthalenediimide) have been studied by time-resolved optical and EPR spectroscopy. Complex 1 is the first synthetically linked electron donor-sensitizer-acceptor triad in which a manganese complex plays the role of the donor. EPR spectroscopy was used to directly demonstrate the light induced formation of both products: the oxidized manganese dimer complex (Mn2II,III) and the reduced naphthalenediimide (NDI*-) acceptor moieties, while optical spectroscopy was used to follow the kinetic evolution of the [Ru(bpy)3]2+ intermediate states and the NDI*- radical in a wide temperature range. The average lifetime of the NDI*- radical is ca. 600 micros at room temperature, which is at least 2 orders of magnitude longer than that for previously reported triads based on a [Ru(bpy)3]2+ photosensitizer. At 140 K, this intramolecular recombination was dramatically slowed, displaying a lifetime of 0.1-1 s, which is comparable to many of the naturally occurring charge-separated states in photosynthetic reaction centra. It was found that the long recombination lifetime could be explained by an unusually large reorganization energy (lambda approximately 2.0 eV), due to a large inner reorganization of the manganese complex. This makes the recombination reaction strongly activated despite the large driving force (Delta-G degrees = 1.07 eV). Thus, the intrinsic properties of the manganese complex are favorable for creating a long-lived charge separation in the "Marcus normal region" also when the charge separated state energy is high.

  • 6.
    Cardona, Tanai
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Battchikova, Natalia
    Agervald, Åsa
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Zhang, Pengpeng
    Nagel, Erik
    Aro, Eva-Mari
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Lindblad, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Magnuson, Ann
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Isolation and characterization of thylakoid membranes from the filamentous cyanobacterium Nostoc punctiforme2007In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 131, no 4, p. 622-634Article in journal (Refereed)
    Abstract [en]

    Nostoc punctiforme strain Pasteur Culture Collection (PCC) 73102, a sequenced filamentous cyanobacterium capable of nitrogen fixation, is used as a model organism for characterization of bioenergetic processes during nitrogen fixation in Nostoc. A protocol for isolating thylakoid membranes was developed to examine the biochem. and biophys. aspects of photosynthetic electron transfer. Thylakoids were isolated from filaments of N. punctiforme by pneumatic pressure-drop lysis. The activity of photosynthetic enzymes in the isolated thylakoids was analyzed by measuring oxygen evolution activity, fluorescence spectroscopy and ESR spectroscopy. Electron transfer was found functional in both PSII and PSI. Electron transfer measurements in PSII, using diphenylcarbazide as electron donor and 2,6-dichlorophenolindophenol as electron acceptor, showed that 80% of the PSII centers were active in water oxidn. in the final membrane prepn. Anal. of the membrane protein complexes was made by 2D gel electrophoresis, and identification of representative proteins was made by mass spectrometry. The ATP synthase, several oligomers of PSI, PSII and the NAD(P)H dehydrogenase (NDH)-1L and NDH-1M complexes, were all found in the gels. Some differences were noted compared with previous results from Synechocystis sp. PCC 6803. Two oligomers of PSII were found, monomeric and dimeric forms, but no CP43-less complexes. Both dimeric and monomeric forms of Cyt b6/f could be obsd. In all, 28 different proteins were identified, of which 25 are transmembrane proteins or membrane associated ones.

  • 7.
    Cardona, Tanai
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Battchikova, Natalia
    Department of Biology, University of Turku.
    Zhang, Pengpeng
    Department of Biology, University of Turku.
    Stensjö, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Microbial Chemistry.
    Aro, Eva-Mari
    Department of Biology, University of Turku.
    Lindblad, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Microbial Chemistry.
    Magnuson, Ann
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Electron transfer protein complexes in the thylakoid membranes of heterocysts from the cyanobacterium Nostoc punctiforme2009In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1787, no 4, p. 252-263Article in journal (Refereed)
    Abstract [en]

    Filamentous, heterocystous cyanobacteria are capable of nitrogen fixation and photoautotrophic growth. Nitrogen fixation takes place in heterocysts that differentiate as a result of nitrogen starvation. Heterocysts uphold a microoxic environment to avoid inactivation of nitrogenase, e.g. by downregulation of oxygenic photosynthesis. The ATP and reductant requirement for the nitrogenase reaction is considered to depend on Photosystem I, but little is known about the organization of energy converting membrane proteins in heterocysts. We have investigated the membrane proteome of heterocysts from nitrogen fixing filaments of Nostoc punctiforme sp. PCC 73102, by 2D gel electrophoresis and mass spectrometry. The membrane proteome was found to be dominated by the Photosystem I and ATP-synthase complexes.We could identify asignificant amount of assembled Photosystem II complexes containing the D1, D2, CP43, CP47 and PsbO proteins from these complexes. We could also measure light-driven in vitro electron transfer from Photosystem II in heterocyst thylakoid membranes. We did not find any partially disassembled PhotosystemII complexes lacking the CP43 protein. Several subunits of the NDH-1 complex were also identified. The relative amount of NDH-1M complexes was found to be higher than NDH-1L complexes, which might suggest a role for this complex in cyclic electron transfer in the heterocysts of Nostoc punctiforme.

  • 8.
    Cardona, Tanai
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Magnuson, Ann
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Excitation energy transfer to Photosystem I in filaments and heterocysts of Nostoc punctiforme2010In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1797, no 3, p. 425-433Article in journal (Refereed)
    Abstract [en]

    Cyanobacteria adapt to varying light conditions by controlling the amount of excitation energy to the photosystems. On the minute time scale this leads to redirection of the excitation energy, usually referred to as state transitions, which involves movement of the phycobilisomes. We have studied short-term light adaptation in isolated heterocysts and intact filaments from the cyanobacterium Nostoc punctiforme ATCC 29133. In N. punctiforme vegetative cells differentiate into heterocysts where nitrogen fixation takes place. Photosystem II is inactivated in the heterocysts, and the abundancy of Photosystem I is increased relative to the vegetative cells. To study light-induced changes in energy transfer to Photosystem I, pre-illumination was made to dark adapted isolated heterocysts. Illumination wavelengths were chosen to excite Photosystem I (708 nm) or phycobilisomes (560. nm) specifically. In heterocysts that were pre-illuminated at 708. nm, fluorescence from the phycobilisome terminal emitter was observed in the 77 K emission spectrum. However, illumination with 560. nm light caused quenching of the emission from the terminal emitter, with a simultaneous increase in the emission at 750 nm, indicating that the 560 nm pre-illumination caused trimerization of Photosystem I. Excitation spectra showed that 560 nm pre-illumination led to an increase in excitation transfer from the phycobilisomes to trimeric Photosystem I. Illumination at 708 nm did not lead to increased energy transfer from the phycobilisome to Photosystem I compared to dark adapted samples. The measurements were repeated using intact filaments containing vegetative cells, and found to give very similar results as the heterocysts. This demonstrates that molecular events leading to increased excitation energy transfer to Photosystem I, including trimerization, are independent of Photosystem II activity.

  • 9. Chakraborty, Jishnunil
    et al.
    Shaikh, Nizamuddin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Mayer-Figge, Heike
    Sheldrick, William S.
    Vojtisek, Pavel
    Banerjee, Pradyot
    Synthesis, crystal, and molecular structure of coordination polymers constructed by self-assembly of NiN4 cores with 2,2 '-iminodibenzoate and nitroprusside ions2007In: Structural Chemistry, ISSN 1040-0400, E-ISSN 1572-9001, Vol. 18, no 2, p. 157-164Article in journal (Refereed)
    Abstract [en]

    Two coordination compounds of compositions [Ni(L-1)(idba)(H2O)]center dot 1.5 H2O (1) and [Ni(L-2)Fe(CN)(5)NO]. C2H5OH (2) where L-1 is N, N-bis(3-aminopropyl)ethylenediamine, L-2 is 2,12-dimethyl-3,7,11,17-tetraazabicyclo [11.3.1]heptadeca-1(17),2,11,13,15-pentaene, and idba(2)- is 2,2'-iminodibenzoate have been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction. Complex I crystallizes in the monoclinic space group P2(1)/n (No. 14) with a = 9.810(2) angstrom, b = 10.230(2) angstrom, c = 25.350(5) angstrom, V = 2543.6(9) angstrom(3), Z = 4, and R = 0.0727. The nickel atom is six-coordinated by four N atoms of amine and two 0 atoms of water and idba2-. The molecular packing of the complex comprises of an infinite one-dimensional layered network in which the molecules in the crystal are held together by a system of hydrogen bonding. Complex 2, however, crystallizes in the space group C2/c (No. 15) of the monoclinic system with a = 19.7990(4) angstrom, b = 14.9440(3) angstrom, c = 19.8800(3) angstrom, V = 5115.90(17) angstrom(3), Z = 4, and R = 0.0540. The Ni ion in compound 2 has a slightly distorted octahedral arrangement of the N-4 donor atoms of primary ligand L-2 and two N-donor atoms of the secondary nitroprusside ligand. The structure of 2 displays an extended one-dimensional network formed by linear [-Ni-NC-Fe-CN-] units. A cyclic voltammetric study shows that compound 1 undergoes a quasireversible oxidation attributable to Ni2+ -> Ni3+ in the range 300-420 mV vs SCE.

  • 10. Cox, Nicholas
    et al.
    Ho, Felix M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Pewnim, Naray
    Steffen, Ronald
    Smith, Paul J.
    Havelius, Kajsa G. V.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Hughes, Joseph L.
    Debono, Lesley
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Krausz, Elmars
    Pace, Ron J.
    The S-1 split signal of photosystem II: a tyrosine-manganese coupled interaction2009In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1787, no 7, p. 882-889Article in journal (Refereed)
    Abstract [en]

    Detailed optical and EPR analyses of states induced in dark-adapted PS II membranes by cryogenic illumination permit characterization and quantification of all pigment derived donors and acceptors, as well as optically silent (in the visible, near infrared) species which are EPR active. Near complete turnover formation of Q(A)(-) is seen in all centers, but with variable efficiency, depending on the donor species. In minimally detergent-exposed PS II membranes, negligible (<5%) oxidation of chlorophyll or carotenoid centers occurs for illumination temperatures 5-20 K. An optically silent electron donor to P680(+) is observed with the same decay kinetics as the S-1 split signal. Cryogenic donors to P680(+) seen are: (i) transient (t(1/2)similar to 150 s) tyrosine related species, including 'split signals' (similar to 15% total centers), (ii) reduced cytochrome b(559) (similar to 30-50% centers), and (iii) an organic donor, possibly an amino acid side chain, (similar to 30% centers).

  • 11. Danielsson, Ravi
    et al.
    Suorsa, Marjaana
    Paakkarinen, Virpi
    Albertsson, Per-Ake
    Styring, Stenbjörn
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Aro, Eva-Mari
    Mamedov, Fikret
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Dimeric and monomeric organization of photosystem II. Distribution of five distinct complexes in the different domains of the thylakoid membrane.2006In: J Biol Chem, ISSN 0021-9258, Vol. 281, no 20, p. 14241-9Article in journal (Refereed)
  • 12.
    Ezzaher, Salah
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Bruhn, Clemens
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Directing protonation in [FeFe] hydrogenase active site models by modifications in their second coordination sphere2010In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 46, no 31, p. 5775-5777Article in journal (Refereed)
    Abstract [en]

    Subtle changes in the second coordination sphere of [Cl(2)bdtFe(2)-(CO)(4)(Ph2P-CH2-X-CH2-PPh2)] (bdt = benzene-1,2-dithiolate, X = NCH3, NCH2CF3, CH2) that do not influence the electronic character of the Fe-2 center can however direct protonation to three different sites: the N in the bis-phosphane, the Fe-Fe bond or the bdt-S.

  • 13.
    Falkenström, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Johansson, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Light-induced charge separation in ruthenium based triads: New variations on an old theme2007In: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 360, no 3, p. 741-750Article, review/survey (Refereed)
    Abstract [en]

    Success with artificial photosynthesis requires control of the photoinduced electron transfer reactions leading to charge-separated states. In this review, some new ideas to optimize such charge-separated states in ruthenium(II) polypyridyl based three-component systems with respect to: (1) long lifetimes and (2) ability to store sufficient energy for catalytic water splitting, are presented. To form long-lived charge-separated states, a manganese complex as electron donor and potential catalyst for water oxidation has been used. The recombination reaction is unusually slow because it occurs deep down in the Marcus normal region as a consequence of the large bond reorganization following the manganese oxidation. For the creation of high energy charge-separated states, a strategy using bichromophoric systems is presented. By consecutive excitations of the two chromophores, the formation of charge-separated states that lie higher in energy than either of the two excited states could in theory be achieved, the first results of which will be discussed in this review.

  • 14. Gasanov, Ralphreed
    et al.
    Aliyeva, Samira
    Arao, Sachiko
    Ismailova, Aygun
    Katsuta, Nobuhiro
    Kitade, Hidetoshi
    Yamada, Shuji
    Kawamori, Asako
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Comparative study of the water oxidizing reactions and the millisecond delayed chlorophyll fluorescence in photosystem II at different pH2007In: Journal of Photochemistry and Photobiology. B: Biology, ISSN 1011-1344, E-ISSN 1873-2682, Vol. 86, no 2, p. 160-164Article in journal (Refereed)
    Abstract [en]

    Water splitting activity, the multiline EPR signal associated with S2-state of the CaMn4-cluster and the fast and slow phases of the induction curve of the millisecond delayed chlorophyll fluorescence from photosystem II (PSII) in the pH range of 4.5–8.5 were studied in the thylakoid membranes and purified PSII particles. It has been found that O2 evolution and the multiline EPR signal were inhibited at acidic (pK 5.3) and alkaline (pK 8.1) pH values, and were maximal at pH 6.0–7.0. Our results indicate that the loss of O2 evolution and the S2-state multiline EPR signal associated with the decrease of the millisecond delayed chlorophyll fluorescence only in alkaline region (pH 7.0–8.5). Possible correlations of the millisecond delayed chlorophyll fluorescence components with the donor side reactions in PSII are discussed.

  • 15.
    Geng, Xue-Li
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Hu, Qi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Schäfer, Bernhard
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Phosphaalkenes in pi-conjugation with Acetylenic Arenes2010In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 12, no 4, p. 692-695Article in journal (Refereed)
    Abstract [en]

    Phosphaalkene inclusion at the periphery of acetylenic arenes results in decreased band gaps of the title compounds as verified by spectroscopic and electrochemical techniques. The electronic coupling between two 1-phosphahex-l-ene-3,5-diyne units is mediated by all paral-substituted arenes and Increases from 4b to 4d.

  • 16.
    Hammarström, Leif
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Johansson, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Expanded bite angles in tridentate ligands: improving the photophysical properties in bistridentate Ru-II polypyridine complexes2010In: Coordination chemistry reviews, ISSN 0010-8545, E-ISSN 1873-3840, Vol. 254, no 21-22, p. 2546-2559Article in journal (Refereed)
    Abstract [en]

    Bistridentate metal complexes as photosensitizers are ideal building blocks in the construction of rodlike isomer-free assemblies for intramolecular photoinduced charge separation. Approaches to obtain long-lived luminescent metal-to-ligand charge transfer excited states in bistridentate Run polypyridine complexes via the manipulation of metal-centered state energies are discussed. Following an introduction to general strategies to prolong the excited state lifetimes, more recent work is explored in detail where tridentate ligands with expanded 2,2':6',2 ''-terpyridine cores are utilized. The synthesis of these tridentate ligands and their corresponding Ru-II complexes is covered. Bistridentate Run complexes with microsecond metal-to-ligand charge transfer excited state lifetimes are described, and are used in electron donor-photosensitizer-electron acceptor assemblies for efficient vectorial photoinduced charge separation.

  • 17.
    Hammarström, Leif
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Physics, Department of Physics and Materials Science, Chemical Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Johansson, Olof
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Physics, Department of Physics and Materials Science, Chemical Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Magnuson, Ann
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Physics, Department of Physics and Materials Science, Chemical Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Artificial Photosynthesis Edited by Anthony F. Collings and Christa Critchley2006In: Angewandte Chemie, International Edition, 2006Chapter in book (Other (popular scientific, debate etc.))
  • 18.
    Han, Guangye
    et al.
    Institute of Botany, The Chinese Academy of Sciences.
    Ho, Felix M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Havelius, Kajsa G. V.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Morvaridi, Susan F.
    Department of Chemistry and Biochemistry, University of California-Los Angeles,.
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Direct quantification of the four individual S states in Photosystem II using EPR spectroscopy2008In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1777, no 6, p. 496-503Article in journal (Refereed)
    Abstract [en]

    Car, carotenoid; Chl, chlorophyll; ChlZ, secondary chlorophyll electron donor to P680+; Cytb559, cytochrome b559; EPR, electron paramagnetic resonance; DMSO, dimethylsulfoxide; MES, 2-(N-morpholino) ethanesulfonic acid; NIR, near-infrared; OEC, oxygen evolving complex; P680, primary electron donor chlorophylls in PSII; PpBQ, phenyl-p-benzoquinone; PSII, Photosystem II; QA and QB, primary and secondary plastoquinone acceptors of Photosystem II; YD, tyrosine 161 of the PSII D2 polypeptide; YZ, tyrosine 161 of the PSII D1 polypeptide

  • 19. Han, Guangye
    et al.
    Morvaridi, Susan
    Ho, Felix
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    S-state dependence of misses in the OEC probed by EPR spectroscopy of individual S-states2008In: Photosynthesis. Energy from the Sun / [ed] Allen J.F., Gant E., Golbeck J.H. and Osmond B., Springer , 2008, p. 419-422Conference paper (Refereed)
  • 20.
    Havelius, Kajsa G. V.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Ho, Felix M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Su, Ji-Hu
    Max Plank Institute for Bioinorganic Chemistry.
    Han, Guangye
    Institute of Botany, The Chinese Academy of Sciences.
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    The same origin of the split EPR signal induced by visible or near-infrared light at liquid helium temperature from the S3-state of photosystem IIManuscript (Other academic)
  • 21.
    Havelius, Kajsa G. V.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Sjöholm, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Ho, Felix M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Metalloradical EPR Signals from the Y-Z center dot S-State Intermediates in Photosystem II2010In: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 37, no 1-4, p. 151-176Article, review/survey (Refereed)
    Abstract [en]

    The redox-active tyrosine residue (Y-Z) plays a crucial role in the mechanism of the water oxidation. Metalloradical electron paramagnetic resonance (EPR) signals reflecting the light-induced Y-Z center dot in magnetic interaction with the CaMn4-cluster in the particular S-state, Y-Z center dot S-X intermediates, have been found in intact photosystem II. These so-called split EPR signals are induced by illumination at cryogenic temperatures and provide means to both study the otherwise transient Y-Z center dot and to probe the S-states with EPR spectroscopy. The illumination used for signal induction grouped the observed split EPR signals in two categories: (i) Y-Z in the lower S-states was oxidized by P680(+) formed via charge separation, while (ii) Y-Z in the higher S-states was oxidized by an excited, highly oxidizing Mn species. Applied mechanistic studies of the Y-Z center dot S-X intermediates in the different S-states are reviewed and compared to investigations in photosystem II at physiological temperature. Addition of methanol induced S-state characteristic changes in the split signals' formation which reflect changes in the magnetic coupling within the CaMn4-cluster due to methanol binding. The pH titration of the split EPR signals, on the other hand, could probe the proton-coupled electron transfer properties of the Y-Z oxidation. The apparent pK (a)s found for decreased split signal induction were interpreted in the fate of the phenol proton.

  • 22.
    Havelius, Kajsa G. V.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    pH Dependent Competition between YZ and YD in Photosystem II Probed by Illumination at 5 K2007In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 46, no 26, p. 7865-7874Article in journal (Refereed)
    Abstract [en]

    The photosystem II (PSII) reaction center contains two redox active tyrosines, YZ and YD, situated on the D1 and D2 proteins, respectively. By illumination at 5 K, oxidation of YZ in oxygen-evolving PSII can be observed as induction of the Split S1 EPR signal from YZ* in magnetic interaction with the CaMn4 cluster, whereas oxidation of YD can be observed as the formation of the free radical EPR signal from YD*. We have followed the light induced induction at 5 K of the Split S1 signal between pH 4-8.5. The formation of the signal, that is, the oxidation of YZ, is pH independent and efficient between pH 5.5 and 8.5. At low pH, the split signal formation decreases with pKa approximately 4.7-4.9. In samples with chemically pre-reduced YD, the pH dependent competition between YZ and YD was studied. Only YZ was oxidized below pH 7.2, but at pH above 7.2, the oxidation of YD became possible, and the formation of the Split S1 signal diminished. The onset of YD oxidation occurred with pKa approximately 8.0, while the Split S1 signal decreased with pKa approximately 7.9 demonstrating that the two tyrosines compete in this pH interval. The results reflect the formation and breaking of hydrogen bonds between YZ and D1-His190 (HisZ) and YD and D2-His190 (HisD), respectively. The oxidation of respective tyrosine at 5 K demands that the hydrogen bond is well-defined; otherwise, the low-temperature oxidation is not possible. The results are discussed in the framework of recent literature data and with respect to the different oxidation kinetics of YZ and YD.

  • 23. Havelius, Kajsa G V
    et al.
    Su, Ji-Hu
    Feyziyev, Yashar
    Mamedov, Fikret
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Spectral resolution of the split EPR signals induced by illumination at 5 K from the S1, S3, and S0 states in photosystem II.2006In: Biochemistry, ISSN 0006-2960, Vol. 45, no 30, p. 9279-90Article in journal (Refereed)
  • 24.
    Havelius, Kajsa G.V.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    EPR Studies of Photosystem II: Characterizing Water Oxidizing Intermediates at Cryogenic Temperatures2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The principles of natures own light-driven water splitting catalyst, Photosystem II (PSII), can in the future inspire us to use water as electron and proton source to generate light-driven H2 production. To mimic this challenging step, it is important to understand how the enzyme system can oxidize water. The mechanism of light-driven water oxidation in PSII is in this thesis addressed by EPR spectroscopy. P680+ is a strong oxidant formed by light-oxidation of the chlorophyll species P680 positioned in the center of PSII. The redox active tyrosine-Z (YZ) can reduce P680+ and the YZ radical is formed. This transient radical is further reduced by the CaMn4-cluster, which is the binding site of the substrate water molecules. In a cyclic process called the S-cycle, this catalytic cluster accumulates four oxidizing equivalents to evolve one molecule of O2 and to oxidize two molecules of water. We can induce the YZ radical at cryogenic temperatures in the different oxidation states of the catalytic S-cycle and observe this in metalloradical EPR signals. These metalloradical EPR signals are here characterized and used to deduce mechanistic information from the intact PSII. The "double nature" of these spin-spin interaction signals, so called split EPR signals, makes them excellent probes to both YZ oxidation and, when YZ is present, also to the S-states of the CaMn4-cluster. The metalloradical EPR signals presented here, form a way to study the transient YZ radical in active PSII that has not been depleted of the catalytic metal cluster. This depleting method that has often been used in the past to study YZ is not representing studies of a mechanistically relevant material. The previously suggested disorder around YZ and accessibility to the bulk can be artifactual properties induced in the mechanistically defect PSII. On the contrary, our observation that proton coupled electron transfer from YZ to the light induced P680+ can occur in a high yield at cryogenic temperatures, suggests a well ordered catalytic site in the protein positioned for optimal performance. The optimized positioning of the redox components found in PSII might be a feature also important to build in an efficient water oxidizing catalyst.

    List of papers
    1. pH Dependent Competition between YZ and YD in Photosystem II Probed by Illumination at 5 K
    Open this publication in new window or tab >>pH Dependent Competition between YZ and YD in Photosystem II Probed by Illumination at 5 K
    2007 (English)In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 46, no 26, p. 7865-7874Article in journal (Refereed) Published
    Abstract [en]

    The photosystem II (PSII) reaction center contains two redox active tyrosines, YZ and YD, situated on the D1 and D2 proteins, respectively. By illumination at 5 K, oxidation of YZ in oxygen-evolving PSII can be observed as induction of the Split S1 EPR signal from YZ* in magnetic interaction with the CaMn4 cluster, whereas oxidation of YD can be observed as the formation of the free radical EPR signal from YD*. We have followed the light induced induction at 5 K of the Split S1 signal between pH 4-8.5. The formation of the signal, that is, the oxidation of YZ, is pH independent and efficient between pH 5.5 and 8.5. At low pH, the split signal formation decreases with pKa approximately 4.7-4.9. In samples with chemically pre-reduced YD, the pH dependent competition between YZ and YD was studied. Only YZ was oxidized below pH 7.2, but at pH above 7.2, the oxidation of YD became possible, and the formation of the Split S1 signal diminished. The onset of YD oxidation occurred with pKa approximately 8.0, while the Split S1 signal decreased with pKa approximately 7.9 demonstrating that the two tyrosines compete in this pH interval. The results reflect the formation and breaking of hydrogen bonds between YZ and D1-His190 (HisZ) and YD and D2-His190 (HisD), respectively. The oxidation of respective tyrosine at 5 K demands that the hydrogen bond is well-defined; otherwise, the low-temperature oxidation is not possible. The results are discussed in the framework of recent literature data and with respect to the different oxidation kinetics of YZ and YD.

    Keywords
    Cold, Electron Spin Resonance Spectroscopy, Hydrogen-Ion Concentration, Models, Chemical, Oxidation-Reduction, Photosystem II Protein Complex/*physiology/radiation effects, Spinacia oleracea, Tyrosine/*metabolism
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-11297 (URN)10.1021/bi700377g (DOI)000247486800018 ()17559194 (PubMedID)
    Available from: 2007-08-28 Created: 2007-08-28 Last updated: 2017-12-11Bibliographically approved
    2. Spectral resolution of the split EPR signals induced by illumination at 5 K from the S1, S3, and S0 states in photosystem II.
    Open this publication in new window or tab >>Spectral resolution of the split EPR signals induced by illumination at 5 K from the S1, S3, and S0 states in photosystem II.
    Show others...
    2006 (English)In: Biochemistry, ISSN 0006-2960, Vol. 45, no 30, p. 9279-90Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-81366 (URN)16866374 (PubMedID)
    Available from: 2006-08-18 Created: 2006-08-18 Last updated: 2011-01-11
    3. Formation Spectra of the EPR Split Signals from the S(0), S(1), and S(3) States in Photosystem II Induced by Monochromatic Light at 5 K
    Open this publication in new window or tab >>Formation Spectra of the EPR Split Signals from the S(0), S(1), and S(3) States in Photosystem II Induced by Monochromatic Light at 5 K
    Show others...
    2007 (English)In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 46, no 37, p. 10703-10712Article in journal (Refereed) Published
    Abstract [en]

    The interaction EPR split signals from photosystem II (PSII) have been reported from the S0, S1, and S3 states. The signals are induced by illumination at cryogenic temperatures and are proposed to reflect the magnetic interaction between YZ* and the Mn4Ca cluster. We have investigated the formation spectra of these split EPR signals induced in PSII enriched membranes at 5 K using monochromatic laser light from 400 to 900 nm. We found that the formation spectra of the split S0, split S1, and split S3 EPR signals were quite similar, but not identical, between 400 and 690 nm, with maximum formation at 550 nm. The major deviations were found between 440 and 480 nm and between 580 and 680 nm. In the regions around 460 and 680 nm the amplitudes of the formation spectra were 25-50% of that at 550 nm. A similar formation spectrum was found for the S2-state multiline EPR signal induced at 0 degrees C. In general, the formation spectra of these signals in the visible region resemble the reciprocal of the absorption spectra of our PSII membranes. This reflects the high chlorophyll concentration necessary for the EPR measurements which mask the spectral properties of other absorbing species. No split signal formation was found by the application of infrared laser illumination between 730 and 900 nm from PSII in the S0 and S1 states. However, when such illumination was applied to PSII membranes poised in the S3 state, formation of the split S3 EPR signal was observed with maximum formation at 740 nm. The quantum yield was much less than in the visible region, but the application of intensive illumination at 830 nm resulted in accumulation of the signal to an amplitude comparable to that obtained with illumination with visible light. The split S3 EPR signal induced by NIR light was much more stable at 5 K (no observable decay within 60 min) than the split S3 signal induced by visible light (50% of the signal decayed within 30 min). The split S3 signals induced by each of these light regimes showed the same EPR spectral features and microwave power saturation properties, indicating that illumination of PSII in the S3 state by visible light or by NIR light produces a similar configuration of YZ* and the Mn4Ca cluster.

    National Category
    Biochemistry and Molecular Biology
    Identifiers
    urn:nbn:se:uu:diva-11415 (URN)10.1021/bi7004174 (DOI)000249433100030 ()17718509 (PubMedID)
    Available from: 2007-09-12 Created: 2007-09-12 Last updated: 2017-12-11Bibliographically approved
    4. Split EPR signals from photosystem II are modified by methanol, reflecting S state-dependent binding and alterations in the magnetic coupling in the CaMn4 cluster.
    Open this publication in new window or tab >>Split EPR signals from photosystem II are modified by methanol, reflecting S state-dependent binding and alterations in the magnetic coupling in the CaMn4 cluster.
    Show others...
    2006 (English)In: Biochemistry, ISSN 0006-2960, Vol. 45, no 24, p. 7617-27Article in journal (Refereed) Published
    Keywords
    Binding Sites, Comparative Study, Dose-Response Relationship; Drug, Electron Spin Resonance Spectroscopy, Lasers, Light, Magnetics, Methanol/*pharmacology, Photosynthetic Reaction Center Complex Proteins/chemistry/genetics/*metabolism, Photosystem II Protein Complex/*metabolism, Protein Binding/drug effects, Research Support; Non-U.S. Gov't, Signal Transduction/drug effects, Spinacia oleracea/metabolism
    Identifiers
    urn:nbn:se:uu:diva-81367 (URN)16768457 (PubMedID)
    Available from: 2006-08-18 Created: 2006-08-18 Last updated: 2011-01-11
    5. The same origin of the split EPR signal induced by visible or near-infrared light at liquid helium temperature from the S3-state of photosystem II
    Open this publication in new window or tab >>The same origin of the split EPR signal induced by visible or near-infrared light at liquid helium temperature from the S3-state of photosystem II
    Show others...
    (English)Manuscript (Other academic)
    Keywords
    Photosystem II, EPR, S3-state, near-infrared
    Identifiers
    urn:nbn:se:uu:diva-99108 (URN)
    Available from: 2009-03-12 Created: 2009-03-09 Last updated: 2012-12-27
    6. Investigation and characterisation of EPR split signals in the native S2 state of Photosystem II
    Open this publication in new window or tab >>Investigation and characterisation of EPR split signals in the native S2 state of Photosystem II
    Show others...
    (English)Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-99340 (URN)
    Available from: 2009-03-12 Created: 2009-03-12 Last updated: 2012-12-27
    7. The S0 state of the water oxidizing complex in photosystem II: pH dependence of the EPR Split signal, induction and mechanistic implications
    Open this publication in new window or tab >>The S0 state of the water oxidizing complex in photosystem II: pH dependence of the EPR Split signal, induction and mechanistic implications
    2009 (English)In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 48, no 40, p. 9393-9404Article in journal (Refereed) Published
    Abstract [en]

    Water oxidation in photosystem II is catalyzed by the CaMn4 cluster.   The electrons extracted from the CaMn4 cluster are transferred to   P-680(+) via the redox-active tyrosine residue D1-Tyr161 (Y-Z). The   oxidation of Y-Z is coupled to a deprotonation creating the neutral   radical Y-Z(center dot). Light-induced oxidation of Y-Z is possible   down to extreme temperatures. This call be observed as a split EPR   signal from Y-Z(center dot) in a magnetic interaction with the CaMn4   cluster, offering a way to probe for Y-Z oxidation in active PSII. Here   we have used the split S-0 EPR signal to study the mechanism of Y-Z   oxidation at 5 K in the S-0 state. The state of the hydrogen bond   between Y-Z and its proposed hydrogen bond partner D1-His190 is   investigated by varying the pH. The split S-0 EPR signal was induced by   illumination at 5 K between pH 3.9 and pH 9.0. Maximum signal intensity   was observed between pH 6 and pH 7. On both the acidic and alkaline   sides the signal intensity decreased with the apparent pK(a)s (pK(app))   similar to 4.8 and similar to 7.9, respectively. The illumination   protocol used to induce the split S-0 EPR signal also induces a mixed   radical signal in the g similar to 2 region. One part of this signal   decays with similar kinetics as the split S-0 EPR signal (similar to 3   min, at 5 K) and is easily distinguished from a stable radical   originating from Car/Chi. We suggest that this fast-decaying radical   originates from Y-Z(center dot). The pH dependence of the light-induced   fast-decaying radical was measured in the same pH range. as for the   split S-0 EPR signal. The pK(app) for the light-induced fast-decaying   radical was identical at acidic pH (similar to 4.8). At alkaline pH the   behavior was more complex. Between pH 6.6 and pH 7.7 the signal   decreased with pK(app) similar to 7.2. However, above pH 7.7 the   induction of the radical species was pH independent. We compare our   results with the pH dependence of the split S-1 EPR signal induced at 5   K and the S-0 -> S-1 and S-1 -> S-2 transitions at room temperature.   The result allows mechanistic conclusions concerning differences   between the hydrogen bond pattern around Y-Z in the S-0 and S-1 states.

    Place, publisher, year, edition, pages
    Easton: American Chemical Society (ACS), 2009
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-99342 (URN)10.1021/bi901177w (DOI)000270459100010 ()
    Available from: 2009-03-12 Created: 2009-03-12 Last updated: 2017-12-13Bibliographically approved
    8. Direct quantification of the four individual S states in Photosystem II using EPR spectroscopy
    Open this publication in new window or tab >>Direct quantification of the four individual S states in Photosystem II using EPR spectroscopy
    Show others...
    2008 (English)In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1777, no 6, p. 496-503Article in journal (Refereed) Published
    Abstract [en]

    Car, carotenoid; Chl, chlorophyll; ChlZ, secondary chlorophyll electron donor to P680+; Cytb559, cytochrome b559; EPR, electron paramagnetic resonance; DMSO, dimethylsulfoxide; MES, 2-(N-morpholino) ethanesulfonic acid; NIR, near-infrared; OEC, oxygen evolving complex; P680, primary electron donor chlorophylls in PSII; PpBQ, phenyl-p-benzoquinone; PSII, Photosystem II; QA and QB, primary and secondary plastoquinone acceptors of Photosystem II; YD, tyrosine 161 of the PSII D2 polypeptide; YZ, tyrosine 161 of the PSII D1 polypeptide

    Keywords
    Photosystem II, Oxygen evolving complex, S states, Split signals, EPR; Misses
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-99345 (URN)10.1016/j.bbabio.2008.03.007 (DOI)000257308600003 ()
    Available from: 2009-03-12 Created: 2009-03-12 Last updated: 2017-12-13
  • 25. Havelius, Kajsa
    et al.
    Su, Ji-Hu
    Ho, Felix
    Han, Guangye
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    The mechanism behind the formation of the “Split S3” EPR signal in photosystem II induced by visible or near-infrared light2008In: Photosynthesis. Energy from the Sun / [ed] Allen J.F., Gant E., Golbeck J.H. and Osmond B., Springer , 2008, p. 423-426Conference paper (Refereed)
  • 26.
    Ho, Felix M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Havelius, Kajsa G. V.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Sjöholm, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Investigation and characterisation of EPR split signals in the native S2 state of Photosystem IIManuscript (Other academic)
  • 27.
    Ho, Felix M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Morvaridi, Susan F.
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Enhancement of Y-D(center dot) spin relaxation by the CaMn4 cluster in photosystem II detected at room temperature: A new probe for the S-cycle2007In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1767, no 1, p. 5-14Article in journal (Refereed)
    Abstract [en]

    The long-lived, light-induced radical Y-D(.) of the Tyr161 residue in the D2 protein of Photosystem 11 (PSII) is known to magnetically interact with the CaMn4 cluster, situated similar to 30 angstrom away. In this study we report a transient step-change increase in YD EPR intensity upon the application of a single laser flash to S, state-synchronised PSII-enriched membranes from spinach. This transient effect was observed at room temperature and high applied microwave power (100 mW) in samples containing PpBQ, as well as those containing DCMU. The subsequent decay lifetimes were found to differ depending on the additive used. We propose that this flash-induced signal increase was caused by enhanced spin relaxation of YD by the OEC in the S-2 state, as a consequence of the single laser flash turnover. The post-flash decay reflected S-2 -> S-1 back-turnover, as confirmed by their correlations with independent measurements of S-2 multiline EPR signal and flash-induced variable fluorescence decay kinetics under corresponding experimental conditions. This flash-induced effect opens up the possibility to study the kinetic behaviour of S-state transitions at room temperature using YD as a probe.

  • 28.
    Huang, P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Kurz, Philipp
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    EPR investigations of synthetic manganese complexes as bio-mimics of the water oxidation complex in photosystem II2007In: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 31, no 1-2, p. 301-320Article in journal (Refereed)
    Abstract [en]

    Research in the Swedish Consortium for Artificial Photosynthesis aims to construct a supramolecular system containing synthetically connected D (electron donor), S (photosensitizer), and A (electron acceptor) compartments. These are intended to carry out catalytic water oxidation on the donor side and catalytic hydrogen formation on the acceptor side, driven by light energy absorbed by the photosensitizer. In this minireview, we focus our attention on our spectroscopic and electrochemical studies of a series of manganese complexes partially mimicking the water-oxidizing manganese complex in the natural photosystem II (PSII), using ruthenium(II) tris(bypyridine) as the photosensitizer. The manganese complexes we discuss fall in three categories: monomeric manganese systems covalently linked to the ruthenium(II) tris(bypyridine) center, dimeric manganese complexes that are not covalently connected to ruthenium(II) tris(bypyridine) and dimeric manganese complexes covalently bound to a ruthenium(II) tris(bypyridine) center via an amide bound. The review focuses on the use of electron paramagnetic resonance spectroscopy in the studies of our manganese compounds.

  • 29.
    Huang, Ping
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Anderlund, Magnus
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Weihe, Högni
    Barra, Anne-Laure
    Sun, Licheng
    Sign of excited spin state magnetic anisotropy parameters.2006In: Spectrochim Acta A Mol Biomol Spectrosc, ISSN 1386-1425, Vol. 63, no 3, p. 541-3Article in journal (Refereed)
  • 30.
    Huang, Ping
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics. Physics, Department of Physics and Materials Science, Chemical Physics.
    Shaikh, Nizamuddin
    Anderlund, Magnus F
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics. Physics, Department of Physics and Materials Science, Chemical Physics.
    Styring, Stenbjörn
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics. Physics, Department of Physics and Materials Science, Chemical Physics.
    Hammarström, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics. Physics, Department of Physics and Materials Science, Chemical Physics.
    Consistent simulation of X- and Q-band EPR spectra of an unsymmetric dinuclear Mn2(II,III) complex.2006In: J Inorg Biochem, ISSN 0162-0134, Vol. 100, no 5-6, p. 1139-46Article in journal (Refereed)
  • 31.
    Johansson, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Pd-catalyzed amination of chloro-terpyridine for the preparation of amine-containing ruthenium(II) complexes2006In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, no 15, p. 2585-2589Article in journal (Refereed)
    Abstract [en]

    The palladium-catalyzed amination reaction of commercially available 4'-chloro-2,2':6',2"-terpyridine opens an easy access to aminated mono- and ditopic terpyridine ligands. The obtained compounds were subsequently used to prepare new amine-containing ruthenium(II) polypyridyl complexes.

  • 32.
    Johansson, Olof
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics. Avdelningen för molekylär biomimetik.
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Rapid electrochemically induced linkage isomerism in a ruthenium(II) polypyridyl complex2005In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 12, p. 1578-80Article in journal (Refereed)
  • 33.
    Jäger, Michael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Smeigh, Amanda
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Lombeck, Florian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Gorls, Helmar
    Collin, Jean-Paul
    Sauvage, Jean-Pierre
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Johansson, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Cyclometalated Ru-II Complexes with Improved Octahedral Geometry: Synthesis and Photophysical Properties2010In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 49, no 2, p. 374-376Article in journal (Refereed)
    Abstract [en]

    Cyclometalated bis-tridentate ruthenium(II) complexes incorporating 2,6-diquinolin-8-ylpyridine ligands and exhibiting broad visible absorptions are described. A [Ru(N boolean AND N boolean AND N)(N boolean AND C boolean AND N)](+) complex based only on ligands with expanded bite angles has a metal-to-ligand charge-transfer excited-state lifetime of 16 ns, which is attributed to a strong ligand field and therefore reduced deactivation via metal-centered states.

  • 34.
    Kaur-Ghumaan, Sandeep
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Schwartz, Lennart
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Stein, Matthias
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Catalytic Hydrogen Evolution from Mononuclear Iron(II) Carbonyl Complexes as Minimal Functional Models of the [FeFe] Hydrogenase Active Site2010In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 49, no 43, p. 8033-8036Article in journal (Refereed)
    Abstract [en]

    How much iron does it take? Mononuclear complexes [FeII(3,6-R2bdt)(CO)2(PMe3)2] (bdt=1,2-C6H4(S)2; R=H, Cl) can be reversibly protonated at the sulfur ligands, can catalyze the electrochemical reduction of protons, and are thus minimal functional models of the [FeFe] hydrogenases (see scheme). DFT calculations show that cleavage of an FeS bond leads to the generation of a free coordination site, which is crucial for the formation of hydrides that are key intermediates in the generation of hydrogen.

  • 35.
    Kumar, Rohan J
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Karlsson, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Streich, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Rolandini Jensen, Alice
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Jäger, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Becker, Hans-Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Johansson, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Vectorial Electron Transfer in Donor-Photosensitizer-Acceptor Triads Based on Novel Bis-tridentate Ruthenium Polypyridyl Complexes2010In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 16, no 9, p. 2830-2842Article in journal (Refereed)
    Abstract [en]

    The first examples of rodlikedonor–photosensitizer–acceptor arrays based on bis-2,6-di(quinolin-8-yl)pyridineRuII complexes 1a and 3a for photoinduced electron transfer have been synthesized and investigated. The complexes are synthesized in a convergent manner and are isolated as linear, single isomers. Time-resolved absorption spectroscopy reveals long-lived, photoinduced charge-separated states(tCSS (1a)=140 ns, tCSS (3a)=200 ns) formed by stepwise electron transfer.The overall yields of charge separation (Yield 50% for complex 1a and Yield 95% for complex 3a) are unprecedented for bis-tridentate RuII polypyridyl complexes.This is attributed to the longlived excited state of the [Ru(dqp)2]2+ complex combined with fast electron transfer from the donor moiety following the initial charge separation. The rodlike arrangement of donor and acceptor gives controlled, vectorial electron transfer, free from the complications of stereoisomeric diversity. Thus, such arrays provide an excellent system for the study of photoinduced electron transfer and, ultimately, the harvesting of solar energy.

  • 36.
    Kurz, Philipp
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Berggren, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Anderlund, Magnus F.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Oxygen evolving reactions catalysed by synthetic manganese complexes: A systematic screening2007In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, no 38, p. 4258-4261Article in journal (Refereed)
    Abstract [en]

    A set of six multinuclear manganese complexes was screened for the ability to catalyse reactions yielding O(2) under coherent experimental conditions; we identify a much larger number of manganese compounds than previously known that catalyse oxygen formation.

  • 37.
    Lomoth, Reiner
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Magnuson, Ann
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Sjödin, Martin
    Huang, Ping
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Mimicking the electron donor side of Photosystem II in artificial photosynthesis.2006In: Photosynthesis Research, ISSN 0166-8595, E-ISSN 1573-5079, p. 1-16Article in journal (Refereed)
  • 38.
    Magnuson, Ann
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics. Avdelningen för molekylär biomimetik.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Hammarström, L.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Chemical Physics.
    Understanding Photosystem II function by artificial photosynthesis2005In: Photosystem II: The Water/Plastoquinone Oxido-Reductase in Photosynthesis / [ed] Wydrzynski, T, Springer, Dordrecht, Netherlands , 2005, p. 753-775Chapter in book (Other academic)
  • 39.
    Mamedov, Fikret
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.