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  • 101.
    Blom, Elisabeth
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Karimi, Farhad
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Use of perfluoro groups in nucleophilic 18F-fluorination2010In: Journal of labelled compounds & radiopharmaceuticals, ISSN 0362-4803, E-ISSN 1099-1344, Vol. 53, no 1, p. 24-30Article in journal (Refereed)
    Abstract [en]

    Substrates with leaving groups that contained perfluoro moieties were investigated in labelling chemistry in order to exploit their properties to improve reactivity and purification. [F-18] (Fluoromethyl) benzene was used as the model target compound. Precursors containing perfluoroalkyl and perfluoroaryl sulfonate moieties were subjected to nucleophilic F-18-fluorination, and the impact of perfluoro groups on the substitution reaction and product purification was investigated. [F-18]Fluoride interacted with perfluoroalkyl chains, precluding nucleophilic substitution. When perfluoroaryl groups were used, the substitution proceeded, and the separation of product was explored. The radiolabelled product was obtained in 32% analytical yield and the radiochemical purity was increased to approximately 77% using fluorous solid phase extraction purification.

  • 102.
    Blom, Elisabeth
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    68Ga-Labeling of Biotin Analogues and their Characterization2009In: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 20, no 6, p. 1146-1151Article in journal (Refereed)
    Abstract [en]

    Biotin- and Ga-68-based tracers have been suggested as tools that could be used to monitor the survival of avidin-coated islets of Langerhans isolated from pancreas and used in transplantation, i.e., to liver. Three biotin analogues with various alkyl and poly(ethylene glycol) (PEG) chains coupled to DOTA were synthesized and labeled with Ga-68. The Ga-68 labeling was studied at room temperature as well as elevated temperature using either conventional or microwave heating. Radioactivity incorporation reached 95% within 5 and 2 min using the, respectively, conventional and microwave heating modes. The specific activity of the tracers was improved by preconcentration and purification of the generator eluate. The binding of the labeled and nonlabeled conjugates to avidin in solution was compared to the binding of native biotim. All compounds maintained good affinity for avidin, though introducing the linkers and chelator, especially the PEG-groups, somewhat decreased the binding affinity. The extent of binding of the labeled compounds to avidin was 54-91% after 5 min. Blocking experiments were performed confirming the specificity of the binding of biotin analogues to avidin. The stability of the three labeled compounds in human serum was studied. The stability of the biotin analogue 8 (65% within 30 min) and avidin-biotin complex (80% within 120 min) might be sufficient for the monitoring of the islets of Langerhans. The tracers will be evaluated in in vitro experiments of avidin-coated islets of Langerhans and in transplantation models in vivo.

  • 103.
    Blom, Elisabeth
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Estrada, Sergio
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Hall, Håkan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Muhammad, Taj
    Ding, Chenmin
    Nair, Manoj
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    68Ga-Labeling of RGD peptides and biodistribution2012In: International Journal of Clinical and Experimental Medicine, ISSN 1940-5901, E-ISSN 1940-5901, Vol. 5, no 2, p. 165-172Article in journal (Refereed)
    Abstract [en]

    Several peptides comprising Arg-Gly-Asp (RGD) domain and macrocyclic chelator were labeled with 68Ga for the imaging of angiogenesis. The analogues varied in peptide constitution, linker and chelator type. The labeling efficiency did not vary with the peptide constitution and linker type, but depended on the chelator type. Four of the compounds containing 2,2',2'',2'''-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) chelator were labeled at 90 ± 5°C using conventional or microwave heating reaching 90% of 68Ga incorporation after 5 and 2 min respectively, when the concentration of the precursor was 2.5 μM. The compound having 2,2',2''-(1,4,7-triazonane-1,4,7-triyl)triacetic acid (NOTA) as the chelator could be labeled at room temperature within 5 min using 2.5 μM peptide precursor. Two of the compounds contained a poly (ethylene glycol) (PEG) linker to the chelator. The biodistribution of the analogues was studied in male rats.

  • 104.
    Blom, Elisabeth
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Velikyan, Irina
    Långström, Bengt
    68Ga-Labelling of RGD peptidesManuscript (preprint) (Other academic)
    Abstract [en]

    Several peptides comprising Arg-Gly-Asp (RGD) domain and macrocyclic chelator were labelled with 68Ga for the imaging of angiogenesis. The analogues varied in peptide constitution, linker and chelator type. The labelling efficiency did not vary with the peptide constitution and linker type, but depended on the chelator type. Four of the compounds containing 2,2',2'',2'''-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) chelator were labelled at 90 ± 5 °C using conventional or microwave heating reaching 90% of 68Ga incorporation after 5 and 2 min respectively, when the concentration of the precursor was 2.5 mM. The compound having 2,2',2''-(1,4,7-triazonane-1,4,7-triyl)triacetic acid (NOTA) as the chelator could be labelled at room temperature within 5 min using 2.5 mM peptide precursor. Two of the compounds contained a poly(ethylene glycol) (PEG) linker to the chelator.

  • 105.
    Blom, Elisabeth
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Monazzam, Azita
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Endocrine Tumor Biology.
    Razifar, Pasha
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Nair, Manoj
    Razifar, Payam
    Vanderheyden, Jean-Luc
    Krivoshein, Arcadius V.
    Backer, Marina
    Backer, Joseph
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Synthesis and characterization of scVEGF-PEG-[68Ga]NOTA and scVEGF-PEG-[68Ga]DOTA PET tracers2011In: Journal of labelled compounds & radiopharmaceuticals, ISSN 0362-4803, E-ISSN 1099-1344, Vol. 54, no 11, p. 685-692Article in journal (Refereed)
    Abstract [en]

    Vascular endothelial growth factor (VEGF) signaling via vascular endothelial growth factor receptor 2 (VEGFR-2) on tumor endothelial cells is a critical driver of tumor angiogenesis. Novel anti-angiogenic drugs target VEGF/VEGFR-2 signaling and induce changes in VEGFR-2 prevalence. To monitor VEGFR-2 prevalence in the course of treatment, we are evaluating (68)Ga positron emission tomography imaging agents based on macrocyclic chelators, site-specifically conjugated via polyethylene glycol (PEG) linkers to engineered VEGFR-2 ligand, single-chain (sc) VEGF. The (68)Ga-labeling was performed at room temperature with NOTA (2,2', 2 ''-(1,4,7-triazonane-1,4,7-triyl) triacetic acid) conjugates or at 90 degrees C by using either conventional or microwave heating with NOTA and DOTA (2,2', 2 '', 2'''-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl) tetraacetic acid) conjugates. The fastest (similar to 2min) and the highest incorporation (>90%) of (68)Ga into conjugate that resulted in the highest specific radioactivity (similar to 400MBq/nmol) was obtained with microwave heating of the conjugates. The bioactivity of the NOTA-and DOTA-containing tracers was validated in 3-D tissue culture model of 293/KDR cells engineered to express high levels of VEGFR-2. The NOTA-containing tracer also displayed a rapid accumulation (similar to 20s after intravenous injection) to steady-state level in xenograft tumor models. A combination of high specific radioactivity and maintenance of functional activity suggests that scVEGF-PEG-[(68)Ga] NOTA and scVEGF-PEG-[(68)Ga] DOTA might be promising tracers for monitoring VEGFR-2 prevalence and should be further explored.

  • 106.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Photoswitchable peptidomimetics with a stiff-stilbene chromophore for inhibition of Mycobacterium tuberculosis RNRManuscript (preprint) (Other academic)
    Abstract [en]

    Peptidomimetics incorporating two amino acids 1 and 2 with a stiff stilbene chromophore have been screened by a computational study and compared to a previously investigated analog 3 with stilbene chromophore. The effect of E-Z isomerization of the chromophores on the conformational properties of the petidomimetics was assessed via the frequency of hydrogen bonding between the two peptide strands attached to either side of the chromophore. Substantial differences between the three amino acids were thus indicated, in line with the anticipated effect of chromophore rigidity variation.

  • 107.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Olsson, Sandra
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Norrehed, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Photomodulable bis-porphyrin molecular tweezers as dynamic host systems for diamine guestsManuscript (preprint) (Other academic)
    Abstract [en]

    Bisporphyrin molecular tweezers with an enediyne (1) or a stiff stilbene (2) photoswitchable spacer are proposed as systems for modulation of bitopic binding to diamine guests via E/Z photoisomerization. The photoisomerization has been monitored by UV-Vis and 1H NMR spectroscopy and occurs without side reactions such as Bergman cyclization. Possible applications are rationalized in terms of competitive binding involving monoamine/diamine mixtures, and are supported by conformational analysis of the envisioned host-guest complexes. Binding dynamics for conformationally flexible guests show significantly different performance of aliphatic 1,w-diamine guests with varying N-N distance.

  • 108.
    Blom, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jafri, Hassan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Di Cristo, Valentina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Carva, Karel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Conduction properties of graphene as a function of ion irradiation and acid treatment2011In: Graphene 2011 - 11th to 14th April 2011. Bilbao, Spain., 2011Conference paper (Refereed)
  • 109.
    Blom, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jafri, Hassan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Widenkvist, Erika
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Quinlan, R A
    Holloway, B C
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    An In-Situ Prepared Nano-Manipulator Tip for Electrical Characterization of Free Standing Graphene Like Sheets Inside a Focused Ion Beam/Scanning Electron Microscope2011In: Journal of Nanoelectronics and Optoelectronics, ISSN 1555-130X, E-ISSN 1555-1318, Vol. 6, no 2, p. 162-168Article in journal (Refereed)
    Abstract [en]

    Although contacting and moving atoms has been demonstrated using probe techniques, for many nano-objects, a fast and reproducible nano-probe technique is needed to acquire a large number of electrical measurements on nano-objects that are often similar but not the identical. Nano-manipulators have become a common tool in many scanning electron microscopes (SEM) and focussed ion beam devices (FIB). They can be rapidly and reproducibly moved from one nano-object to another. In this work we present a procedure to obtain reproducible electrical measurements of nano- to micron-sized objects by using a sharp, tungsten tip with well defined surface properties. The tip is a part of a manipulator and is sharpened in-situ by using the gallium ion beam inside a focused ion beam/scanning electron microscope (FIB/SEM). The contact resistance between a Au surface and the tip is 70 kΩ before the sharpening procedure and 10 Ω after sharpening. The leakage current of the total set-up of 10pA makes it possible to measure currents through a variety of nano-objects. This measurement technique is applied to measure the resistance of as grown, water treated and two HCl treated carbon nanosheets (CNS). These CNS vary in size and morphology. Using this nano-contacting set-up, we could obtain measurements of more than 400 different CNS. The obtained histograms allow us to observe a clear decrease of the resistance between original and 3 hour acid treated CNSs. We observe that longer periods of exposure of the CNS to the HCl do not further modify the resistance.

  • 110. Bodin, Karl
    et al.
    Andersson, Ulla
    Rystedt, Eva
    Ellis, Eva
    Norlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Biochemistry.
    Pikuleva, Irina
    Eggertsen, Gösta
    Björkhem, Ingemar
    Diczfalusy, Ulf
    Metabolism of 4 beta -hydroxycholesterol in humans2002In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 277, no 35, p. 31534-31540Article in journal (Refereed)
    Abstract [en]

    One of the major oxysterols in the human circulation is 4 beta-hydroxycholesterol formed from cholesterol by the drug-metabolizing enzyme cytochrome P450 3A4. Deuterium-labeled 4 beta-hydroxycholesterol was injected into two healthy volunteers, and the apparent half-life was found to be 64 and 60 h, respectively. We have determined earlier the half-lives for 7 alpha-, 27-, and 24-hydroxycholesterol to be approximately 0.5, 0.75, and 14 h, respectively. Patients treated with certain antiepileptic drugs have up to 20-fold increased plasma concentrations of 4 beta-hydroxycholesterol. The apparent half-life of deuterium-labeled 4 beta-hydroxycholesterol in such a patient was found to be 52 h, suggesting that the high plasma concentration was because of increased synthesis rather than impaired clearance. 4 beta-Hydroxycholesterol was converted into acidic products at a much slower rate than 7 alpha-hydroxycholesterol in primary human hepatocytes, and 4 beta-hydroxycholesterol was 7 alpha-hydroxylated at a slower rate than cholesterol by recombinant human CYP7A1. CYP7B1 and CYP39A1 had no activity toward 4 beta-hydroxycholesterol. These results suggest that the high plasma concentration of 4 beta-hydroxycholesterol is because of its exceptionally slow elimination, probably in part because of the low rate of 7 alpha-hydroxylation of the steroid. The findings are discussed in relation to a potential role of 4 beta-hydroxycholesterol as a ligand for the nuclear receptor LXR.

  • 111.
    Bohl Kullberg, Erika
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Bergstrand, Nill
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Carlsson, Jörgen
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Johnsson, Markus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Sjöberg, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Gedda, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Development of EGF-conjugated liposomes for targeted delivery of boronated DNA-binding agents2002In: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 13, no 4, p. 737-743Article in journal (Refereed)
    Abstract [en]

    Liposomes are of interest as drug delivery tools for therapy of cancer and infectious diseases. We investigated conjugation of epidermal growth factor, EGF, to liposomes using the micelle-transfer method. EGF was conjugated to the distal end of PEG−DSPE lipid molecules in a micellar solution and the EGF−PEG−DSPE lipids were then transferred to preformed liposomes, either empty or containing the DNA-binding compound, water soluble acridine, WSA. We found that the optimal transfer conditions were a 1-h incubation at 60 °C. The final conjugate, 125I-EGF−liposome−WSA, contained approximately 5 mol % PEG, 10−15 EGF molecules at the liposome surface, and 104 to 105 encapsulated WSA molecules could be loaded. The conjugate was shown to have EGF-receptor-specific cellular binding in cultured human glioma cells.

  • 112.
    Boija, Elisabet
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Johansson, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Interactions between model membranes and lignin-related compounds studied by immobilized liposome chromatography2006In: Biochimica et Biophysica Acta - Biomembranes, ISSN 0005-2736, E-ISSN 1879-2642, Vol. 1758, no 5, p. 620-626Article in journal (Refereed)
    Abstract [en]

    In order to elucidate the modes of interaction between lignin precursors and membranes, we have studied the influence of temperature, lipid composition and buffer composition on the partitioning of monolignol and dilignol model substances into phospholipid bilayers. The partitioning was determined by immobilized liposome chromatography, which is an established method for studies of pharmaceutical drugs but a new approach in studies of lignin synthesis. The temperature dependence of the retention and the effect of a high ammonium sulfate concentration in the mobile phase demonstrated that the interaction involved both hydrophobic effects and polar interactions. There was also a good correlation between the partitioning and the estimated hydrophobicity, in terms of octanol/water partitioning. The partitioning behavior of the model substances suggests that passive diffusion over the cell membrane is a possible transport route for lignin precursors. This conclusion is strengthened by comparison of the present results with the partitioning of pharmaceutical drugs that are known to pass cell membranes by diffusion.

  • 113.
    Boija, Elisabet
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Lundquist, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Johansson, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Evaluation of bilayer disks as plant cell membrane models in partition studies2007In: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 364, no 2, p. 145-152Article in journal (Refereed)
    Abstract [en]

    We have studied the partitioning of a set of phenolic compounds used as lignin precursor models into lipid bilayer disks and liposomes. The bilayer disks are open bilayer structures stabilized by polyethylene glycol-conjugated lipids. Our results indicate that disks generate more accurate partition data than do liposomes. Furthermore, we show that the partitioning into the membrane phase is reduced slightly if disks composed of 1,2-distearoyl-sn-glycero-3-phosphocholine and cholesterol are exchanged for disks with a lipid composition mimicking that of the root tissue of Zea mays L.

  • 114.
    Boija, Elisabet
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Lundquist, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Nilsson, Mikael
    Department of Chemistry and Biomedical Sciences, University of Kalmar, Kalmar, Sweden.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Isaksson, Roland
    Department of Chemistry and Biomedical Sciences, University of Kalmar, Kalmar, Sweden.
    Johansson, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Bilayer disk capillary electrophoresis: a novel method to study drug partitioning into membranes2008In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 29, no 16, p. 3377-3383Article in journal (Refereed)
    Abstract [en]

    CE in the presence of lipid bilayer disks was introduced as a new approach in membrane partitioning studies. The disks were used as a pseudostationary phase in the partial-filling mode of CE and the partitioning of cationic drugs was determined. The migration times of the analytes increased linearly with the lipid amount in the system. An appropriate algorithm for the calculation of a partition coefficient is presented. In the disk-shaped bilayers, which have excellent stability and shelf life, all of the lipids are readily available for interaction and the disks can be used as realistic cell membrane models.

  • 115.
    Borges, João Batista
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Ulin, Johan
    Maripuu, Enn
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Medical Physics.
    Sandström, Mattias
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Widström, Charles
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Medical Physics.
    Hedenstierna, Göran
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology.
    Ventilation Distribution Studies Comparing Technegas and "Gallgas" Using (GaCl3)-Ga-68 as the Label2011In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 52, no 2, p. 206-209Article in journal (Refereed)
    Abstract [en]

    Ventilation distribution can be assessed by SPECT with Technegas. This study was undertaken in piglets with different degrees of ventilation inhomogeneity to compare PET using Ga-68-labeled pseudogas or "Gallgas" with Technegas. Methods: Twelve piglets were studied in 3 groups: control, lobar obstruction, and diffuse airway obstruction. Two more piglets were assessed for lung volume (functional residual capacity). Results: In controls, SPECT and PET images showed an even distribution of radioactivity. With lobar obstruction, the absence of ventilation of the obstructed lobe was visible with both techniques. In diffuse airway obstruction, SPECT images showed an even distribution of radioactivity, and PET images showed more varied radioactivity over the lung. Conclusion: PET provides detailed ventilation distribution images and a better appreciation of ventilation heterogeneity. Gallgas with PET is a promising new diagnostic tool for the assessment of ventilation distribution.

  • 116.
    Bose, Partha Pratim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Banerjee, Arindam
    Template-directed nucleation and growth of CdS nanocrystal: the role of helical and nonhelical nanofibers on their shape and size2010In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 12, no 3, p. 713-718Article in journal (Refereed)
    Abstract [en]

    This study describes the use of chiral nature of synthetic self-assembled nanofibers for nucleation and growth of Cadmium sulfide (CdS) nanocrystals with different sizes and shapes in room temperature. The templates are built by immobilizing a peptide capping agent on the surface of synthetic self-assembled helical or nonhelical nanofibers and CdS nanocrystals were allowed to grow on them. It is observed that there are differences in shapes and sizes of the nanocrystals depending on the chiral nature of the nanofibers on which they were growing. Even the CdS nanocrystals grown on different chiral and achiral nanofibers differ markedly in their photoluminescence properties. Thus, here we introduce a new way of using chirality of nanofibers to nucleate and grow CdS nanocrystals of different shape, size, and optical property.

  • 117.
    Bose, Partha Pratim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Chatterjee, Urmimala
    Hubatsch, Ina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Artursson, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Govender, Thavendran
    Kruger, Hendrik G.
    Bergh, Margareta
    Johansson, Jan
    Arvidsson, Per I.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    In vitro ADMET and physicochemical investigations of poly-N-methylated peptides designed to inhibit Aβ aggregation2010In: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 18, no 16, p. 5896-5902Article in journal (Refereed)
    Abstract [en]

    N-Methylation is a common strategy for improving oral bioavailability of peptide-based lead structures. Herein, we present a detailed study on how the degree of N-methylation affects the absorption-distribution-metabolism-excretion-toxicity (ADMET) properties such as solubility, membrane transport, proteolytic stability, and general cell toxicity of the investigated peptides. As representative structures we chose hexapeptides 1-8. These peptides, corresponding to N-methylated analogues of residues 16-21 and 32-37 of the Abeta-peptide, pathological hallmark of Alzheimer's disease (AD), have previously been shown to inhibit aggregation of Abeta fibrils in vitro. This study suggests that poly-N-methylated peptides are non-toxic and have enhanced proteolytic stability over their non-methylated analogues. Furthermore, solubility in aqueous solution is seen to increase with increased degree of N-methylation, while membrane transport was found to be low for all investigated hexapeptides. The present results, together with those reported in the literature, suggest that poly-N-methylated peptides, especially shorter or equal to six residues, can be suitable candidates for drug design.

  • 118.
    Bose, Partha Pratim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Chatterjee, Urmimala
    Xie, Ling
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Johansson, Jan
    Göthelid, Emmanuelle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Arvidsson, Per I.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Effects of Congo Red on A beta(1-40) Fibril Formation Process and Morphology2010In: ACS CHEMICAL NEUROSCIENCE, ISSN 1948-7193, Vol. 1, no 4, p. 315-324Article in journal (Refereed)
    Abstract [en]

    Alzheimer's disease (AD), an age-related neurodegenerative disorder, is the most common form of dementia, and the seventh-leading cause of death in the United States. Current treatments offer only symptomatic relief; thus, there is a great need for new treatments with disease-modifying potential. One pathological hallmark of AD is so-called senile plaques, mainly made up of beta-sheet-rich assemblies of 40- or 42-residue amyloid beta-peptides (A beta). Hence, inhibition of A beta aggregation is actively explored as an option to prevent or treat AD. Congo red (CR) has been widely used as a model antiamyloid agent to prevent A beta aggregation. Herein, we report detailed morphological studies on the effect of CR as an antiamyloid agent, by circular dichroism spectroscopy, photo-induced cross-linking reactions, and atomic force microscopy. We also demonstrate the effect of CR on a preaggregated sample of A beta(1-40). Our result suggests that A beta(1-40) follows a different path for aggregation in the presence of CR.

  • 119. Brandt, Peter
    et al.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Exploring the Chemistry of 3-Substituted 2-Azanorbornyls in Asymmetric Catalysis2000In: Synlett, no 8, p. 1092-1106Article in journal (Refereed)
    Abstract
  • 120. Brandt, Peter
    et al.
    Geitmann, Matthis
    Danielson, U Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Biochemistry.
    Deconstruction of Non-Nucleoside Reverse Transcriptase Inhibitors of Human Immunodeficiency Virus Type 1 for Exploration of the Optimization Landscape of Fragments2011In: Journal of Medicinal Chemistry, ISSN 0022-2623, E-ISSN 1520-4804Article in journal (Refereed)
    Abstract [en]

    This study has taken a closer look at the theoretical basis for protein-fragment interactions. The approach involved the deconstruction of 3 non-nucleoside inhibitors of HIV-1 reverse transcriptase and investigation of the interaction between 21 substructures and the enzyme. It focused on the concept of ligand efficiency and showed that ligand independent free energy fees (ΔG(ind)) are crucial for the understanding of the binding affinities of fragments. A value of 7.0 kcal mol(-1) for the ΔG(ind) term is shown to be a lower limit for the NNRTI binding pocket of HIV-1 RT. The addition of the ΔG(ind) term to the dissociation free energy in the calculation of a corrected ligand efficiency, in combination with the lack of an efficient ligand binding hot spot in the NNIBP, fully explains the existence of nonbinding NNRTI substructures. By applying the concept to a larger set of ligands, we could define a binding site profile that indicates the absence of an efficient fragment binding hot spot but an efficient binding of full-sized NNRTIs. The analysis explains some of the challenges in identifying fragments against flexible targets involving conformational changes and how fragments may be prioritized.

  • 121. Brandt, Peter
    et al.
    Hedberg, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    New Mechanistic Insights into the Iridium-Phosphanooxazoline-Catalyzed Hydrogenation of Unfunctionalized Olefins: A DFT and Kinetic Study2003In: Chem. Eur. J., no 9, p. 339-347Article in journal (Refereed)
    Abstract
  • 122. Brandt, Peter
    et al.
    Hedberg, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Lawonn, Klaus
    Pinho, Pedro
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    A Theoretical and Experimental Study of the Asymmetric Addition of Dialkylzinc to N-(Diphenylphosphinoyl)benzalimine1999In: Chem. Eur. J., no 5, p. 1692-1699Article in journal (Refereed)
    Abstract
  • 123. Brandt, Peter
    et al.
    Roth, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Origin of Enantioselectivity in the Ru(arene)(amino alcohol)-Catalyzed Transfer Hydrogenation of Ketones2004In: J. Org. Chem., no 69, p. 4885-4890Article in journal (Refereed)
    Abstract
  • 124.
    Brandt, Peter
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Södergren, Mikael
    Andersson, Pher
    Department of Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Norrby, Per-Ola
    Mechanistic Studies of Copper-Catalyzed Alkene Aziridination2000In: J. Am. Chem. Soc., ISSN 0002-7863, no 122, p. 8013-8020Article in journal (Refereed)
  • 125. Brunnström, Åsa
    et al.
    Hamberg, Mats
    Griffiths, William J.
    Mannervik, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Biochemistry.
    Claesson, Hans-Erik
    Biosynthesis of 14,15-Hepoxilins in Human L1236 Hodgkin Lymphoma Cells and Eosinophils2011In: Lipids, ISSN 0024-4201, E-ISSN 1558-9307, Vol. 46, no 1, p. 69-79Article in journal (Refereed)
    Abstract [en]

    Hepoxilins are epoxy alcohols synthesized through the 12-lipoxygenase (12-LO) pathway in animal cells. The epidermis is the principal source of hepoxilins in humans. Here we report on the formation of novel hepoxilin regioisomers formed by the 15-LO pathway in human cells. The Hodgkin lymphoma cell line L1236 possesses high 15-lipoxygenase-1 (15-LO-1) activity and incubation of L1236 cells with arachidonic acid led to the formation of 11(S)-hydroxy-14(S),15(S)-epoxy 5(Z),8(Z),12(E) eicosatrienoic acid (14,15-HxA(3) 11(S)) and 13(R)-hydroxy-14(S),15(S)-epoxy 5(Z),8(Z),11(Z) eicosatrienoic acid (14,15-HxB(3) 13 (R)). In addition, two hitherto unidentified products were detected and these products were collected and analyzed by positive ion electrospray tandem mass spectrometry. These metabolites were identified as 11(S),15(S)-dihydroxy-14(R)-glutathionyl-5(Z),8(Z),12(E)-eicosatrienoic acid (14,15-HxA(3)-C) and 11(S),15(S)-dihydroxy-14(R)-cysteinyl-glycyl-5(Z),8(Z),12(E)-eicosatrien oic acid (14,15-HxA(3)-D). Incubation of L1236 cells with synthetic 14,15-HxA(3) 11(S) also led to the formation of 14,15-HxA(3)-C and 14,15-HxA(3)-D. Several soluble glutathione transferases, in particular GST M1-1 and GST P1-1, were found to catalyze the conversion of 14,15-HxA(3) to 14,15-HxA(3)-C. L1236 cells produced approximately twice as much eoxins as cysteinyl-containing hepoxilins upon stimulation with arachidonic acid. Human eosinophils, nasal polyps and dendritic cells selectively formed 14,15-HxA(3) 11(S) and 14,15-HxB(3) 13(R) stereoisomers, but not cysteinyl-containing hepoxilins, after stimulation with arachidonic acid. Furthermore, purified recombinant 15-LO-1 alone catalyzed the conversion of arachidonic acid to 14,15-HxA(3) 11(S) and 14,15-HxB(3) 13(R), showing that human 15-LO-1 possesses intrinsic 14,15-hepoxilin synthase activity.

  • 126.
    Bruskin, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Sivaev, Igor
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Persson, Mikael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Lundqvist, Hans
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Carlsson, Jörgen
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Sjöberg, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Radiobromination of monoclonal antibody using potassium [76Br] (4 isothiocyanatobenzyl-ammonio)-bromo-decahydro-closo-dodecaborate (Bromo-DABI)2004In: Nuclear Medicine and Biology, ISSN 0969-8051, E-ISSN 1872-9614, Vol. 31, no 2, p. 205-11Article in journal (Refereed)
    Abstract [en]

    The use of charged linkers in attaching radiohalogens to tumor-seeking biomolecules may improve intracellular retention of the radioactive label after internalization and degradation of targeting proteins. Derivatives of polyhedral boron clusters, such as closo-dodecaborate (2-) anion, might be possible charged linkers. In this study, a bifunctional derivative of closo-dodecaborate, (4-isothiocyanatobenzyl-ammonio)-undecahydro-closo-dodecaborate (DABI) was labeled with positron-emitting nuclide (76)Br (T 1/2 = 16.2 h) and coupled to anti-HER2/neu humanized antibody Trastuzumab. The overall labeling yield at optimized conditions was 80.7 +/- 0.6%. The label was proven to be stable in vitro in physiological and a set of denaturing conditions. The labeled antibody retained its capacity to bind to HER-2/neu antigen expressing cells. The results of the study demonstrated feasibility for using derivatives of closo-dodecaborate in indirect labeling of antibodies for radioimmunoPET.

  • 127.
    Buttner, Frank
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. avd för organisk kemi.
    Norgren, Anna
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. avd för organisk kemi.
    Zhang, Suode
    Prabpai, Samran
    Kongsaeree, Palangpon
    Arvidsson, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. avd för organisk kemi.
    Cyclic B-Tetra- and Pentapeptides: Synthesis through On-Resin Cyclization and Confomrational Studies by X-Ray, NMR and CD Spectroscopy and Theoretical Calculations2005In: Chem. Eur. J., Vol. 11, p. 6145-6158Article in journal (Refereed)
    Abstract [en]

    The solution-phase synthesis of the simplest cyclic B-tetrapeptide, cyclo(B-Ala)4 (4), as well as the solidphase syntheses through side chain anchoring and on-resin cyclization of the cyclic B3-tetrapeptide cyclo-(B3hPhe-B3hLeu-B3hLys-B3hGln-) (14) and the first cyclic B3-pentapeptide cyclo- (B3hVal-B3hPhe-B3Leu- B3hLys-B3hLys-) (19) are reported. Extensive computational as well as spectroscopic studies, including X-ray and NMR spectroscopy, were undertaken to determine the preferred conformations of these unnatural oligomers in solution and in the solid state. cyclo(B-Ala)4 (4) with no chiral side chains is shown to exist as a mixture of rapidly interchanging conformers in solution, whereas inclusion of chiral side chains in the cyclo-B3-tetrapetpride causes stabilizaton of one dominating conformer. The cyclic B3-pentapeptide on the other hand shows larger conformational freedom. The X-ray structure of achiral cyclo(B-Ala)4 (4) displays a Ci-symmetrical 16-membered ring with adjacent C=O and N-H atoms pointing pair wise up and down with respect to the ring plane. CD spectorscopic examinations of all cyclic B-peptides were undertaken and revealed results valuable as starting point for further structural investigations of these entities.

  • 128.
    Byrne, Christopher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Church, Tamara
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Kramer, John
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Coates, Geoffrey
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Catalytic Synthesis of B3-Amino Acid Derivatives from a-Amino Acids***2008In: Angew. Chem. Int. Ed., no 47, p. 3979-3983Article in journal (Refereed)
  • 129. Bäckvall, Jan-E.
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Intramolecular Palladium-Catalyzed 1,4-Addition to Conjugated Dienes. Stereoselective Synthesis of Fused Tetrahydrofurans and Tetrahydropyrans1992In: J. Am. Chem. Soc, Vol. 114, no 16, p. 6374-6381Article in journal (Refereed)
  • 130. Bäckvall, Jan-E.
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Palaldium-Catalyzed Stereocontrolled Intramolecular 1,4-Additions to Cyclic 1,3-Dienes Involving Amides as Nucleophiles1990In: J. Am. Chem. Soc, Vol. 112, no 9, p. 3683-3685Article in journal (Refereed)
  • 131. Bäckvall, Jan-E.
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Stereocontrolled Oxaspirocyclization of Conjugated Dienes via Palladium Catalysis1991In: J. Org. Chem. Soc, Vol. 56, no 7, p. 2274-2276Article in journal (Refereed)
  • 132. Bäckvall, Jan-E.
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Vågberg, Jan O.
    Stereocontrolled Lactonization Reactions via Palladium-Catalysis1989In: Tetrahedron Letters, Vol. 30, no 1, p. 137-140Article in journal (Refereed)
  • 133.
    Bäckvall, Jan-E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Granberg, Kennth L.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Gatti, Roberto
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Stereocontrolled Lactonization Reactions via Palladium-Catalyzed 1,4-Addittion to Conjugated Dienes1993In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 58, no 20, p. 5445-5451Article in journal (Refereed)
    Abstract [en]

    Stereocontrolledp alladium(I1)-catalyzed1 ,4-chloro-and 1,4-acetoxylactonizations o f conjugated cyclic dienes have been developed to give stereodefined fused lactones. The stereochemistry of the 1,4- acetoxylactonization was controlled by the ligand on the metal catalyst, and in this way either a cisor truns-acetoxylactonization was obtained. This dual stereoselectivity is explained by a stereocontrolled acetate attack (trans or cis, respectively) on the allyl group in the catalytic (π-allyl)- palladium intermediate. To further strengthen the mechanism the intermediate (π-ally1)palladium complex was isolated and fully characterized. A stereospecific synthesis of cis-  and truns-2-[6- (benzyloxy)-2,4-heptadien-l-yllacetic a cid (cis-  and truns-9) followed by stereoselective Pd(I1)- catalyzed chloro- and acetoxylactonization in acetonelacetic acid resulted in highly functionalized fused lactones with control of the relative stereochemistry at four different carbons.

  • 134. Bäckvall, Jan-E.
    et al.
    Nilsson, Ylva
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Gatti, Roberto
    Wu, Jinchang
    Carbon-Carbon Bond Formation in Palladium(II)-Catalyzed Intramolecular 1,4-Oxidation of Conjugated Dienes1994In: Tetrahedron Letters, Vol. 35, no 31, p. 5713-5716Article in journal (Refereed)
  • 135.
    Bäckvall, Jan-Erling
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Evidence for (π-allyl)palladium(II)(quinone) complexes in the palladium-catalyzed 1,4-diacetoxylation of conjugated dienes1988In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 29, no 18, p. 2243-2246Article in journal (Refereed)
    Abstract [en]

    Evidence for a coordination of p-benzoquinone to palladium in [4-acetoxy-η3-(1,2,3)-cyclohexenyl]-palladium(II) complexes was provided by changes of the 1H NMR chemical shift values of the π-allyl protons and a decrease of the spin-lattice relaxation time constant for the p-benzoquinone protons.

    The intermediate (π-allyl)palladium(benzoquinone) complexes previously postulated in palladium-catalyzed 1,4-oxidations of 1,3-dienes were detected by NMR spectroscopy.

  • 136.
    Bäckvall, Jan-Erling
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Palladium‑Hydroquinone Catalysed Electrochemical 1,4‑Oxidation of Conjugated Dienes1987In: Journal of the Chemical Society. Chemical communications, ISSN 0022-4936, Vol. 16, p. 1236-1238Article in journal (Refereed)
    Abstract [en]

    The mediator system palladium(II)–hydroquinone was shown to catalyse the anodic oxidation of cyclohexa-1,3-diene in acetic acid to produce selectively either trans- or cis-1,4-diacetoxycyclohex-2-ene (1) depending on the conditions.

  • 137.
    Bökman, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Bohman, Ove
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Pettersson, L. G. M.
    UNIV STOCKHOLM, DEPT THEORET PHYS, S-11346 STOCKHOLM, SWEDEN.
    Siegbahn, Hans O. G.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics.
    Electronic Structure of Catalytically Important Palladium Complexes Studied by Photoelectron Spectroscopy1992In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 11, no 5, p. 1784-1788Article in journal (Refereed)
  • 138.
    Büttner, Frank
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Erdélyi, Máté
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Arvidsson, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    cyclo(ß-Asp-ß3-hVal-ß3-hLys)-Solid-Phase Synthesis and Solution Structure of a Water Soluble ß-Tripeptide2004In: Helvetica Chimica Acta, Vol. 87, p. 2735-2741Article in journal (Refereed)
  • 139.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Paptchikhine, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Birch Reaction Followed by Asymmetric Iridium-Catalysed Hydrogenation2011In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, no 23, p. 3796-3800Article in journal (Refereed)
    Abstract [en]

    Birch reaction products are asymmetrically hydrogenated with high enantio- and diastereoselectivity via iridium catalysts. This new method of producing chiral compounds was explored for a variety of 1,3-di- and 1,2,4-tri-substituted cyclohexadienes.

  • 140. Cassimjee, Karim Engelmark
    et al.
    Kourist, Robert
    Lindberg, Diana
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Wittrup Larsen, Marianne
    Thanh, Nguyen Hong
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Biochemistry.
    Bornscheuer, Uwe T
    Berglund, Per
    One-step enzyme extraction and immobilization for biocatalysis applications2011In: Biotechnology Journal, ISSN 1860-6768, Vol. 6, no 4, p. 463-469Article in journal (Refereed)
    Abstract [en]

    An extraction/immobilization method for HIs(6) -tagged enzymes for use in synthesis applications is presented. By modifying silica oxide beads to be able to accommodate metal ions, the enzyme was tethered to the beads after adsorption of Co(II). The beads were successfully used for direct extraction of C. antarctica lipase B (CalB) from a periplasmic preparation with a minimum of 58% activity yield, creating a quick one-step extraction-immobilization protocol. This method, named HisSi Immobilization, was evaluated with five different enzymes [Candida antarctica lipase B (CalB), Bacillus subtilis lipase A (BslA), Bacillus subtilis esterase (BS2), Pseudomonas fluorescence esterase (PFE), and Solanum tuberosum epoxide hydrolase 1 (StEH1)]. Immobilized CalB was effectively employed in organic solvent (cyclohexane and acetonitrile) in a transacylation reaction and in aqueous buffer for ester hydrolysis. For the remaining enzymes some activity in organic solvent could be shown, whereas the non-immobilized enzymes were found inactive. The protocol presented in this work provides a facile immobilization method by utilization of the common His(6) -tag, offering specific and defined means of binding a protein in a specific location, which is applicable for a wide range of enzymes.

  • 141.
    Chaga, Grigoriy
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Biochemistry.
    Andersson, Lennart
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Porath, Jerker
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Biochemistry.
    Danielson, U Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Biochemistry.
    Mannervik, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Engineering of a metal coordinating site into human glutathione transferase M1-1 based on immobilized metal ion affinity chromatography of homologous rat enzymes1994In: Protein Engineering, ISSN 0269-2139, E-ISSN 1460-213X, Vol. 7, no 9, p. 1115-1119Article in journal (Refereed)
    Abstract [en]

    Rat glutathione transferase (GST) 3-3 binds to Ni(II)-iminodiacetic acid (IDA)-agarose, whereas other GSTs that are abundant in rat liver do not bind to this immobilized metal ion affinity chromatography (IMAC) adsorbent. Rat GST 3-3 contains two superficially located amino acid residues, His84 and His85, that are suitably positioned for coordination to Ni(II)-IDA-agarose. This particular structural motif is lacking in GSTs that do not bind to the IMAC matrix. Creation of an equivalent His-His structure in the homologous human GST M1-1 by protein engineering afforded a mutant enzyme that displays affinity for Ni(II)-IDA-agarose, in contrast to the wild-type GST M1-1. The results identify a distinct site that is operational in IMAC and suggest an approach to the rational design of novel integral metal coordination sites in proteins.

  • 142.
    Chajara, Khalil
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Lu, Jun
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Widenkvist, Erika
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Reagent-free Microwave-assisted Purification of Carbon Nanotubes2010In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 34, no 10, p. 2275-2280Article in journal (Refereed)
  • 143.
    Chajara, Khalil
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Luo, Jun
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microstructure Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Widenkvist, Erika
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    The reagent-free, microwave-assisted purification of carbon nanotubes2010In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 34, no 10, p. 2275-2280Article in journal (Refereed)
    Abstract [en]

    We have developed a microwave-assisted, reagent-free method for the efficient primary purification of MW and SW carbon nanotubes that is extremely fast compared to previously reported processes. The treatment dissociates and disperses non-nanotube carbon in an organic solvent to yield very pure carbon nanotubes within a few minutes of heating and a simple filtration, without the involvement of acidic/oxidative reagents. According to thermogravimetric analysis, Raman and IR spectroscopy, as well as scanning and transmission electron microscopy, the process yields pure nanotubes with a low degree of defects.

  • 144.
    Chajara, Khalil
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Organisk kemi.
    Ottosson, Henrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Organisk kemi.
    An improved pathway to 6,6-disubstituted fulvenes2004In: Tetrahedron Letters, no 45, p. 6741-6744Article in journal (Refereed)
    Abstract [en]

    Pentafulvenes with alkyl and/or aryl substituents at the exocyclic position are formed rapidly in high yields through reaction of crystalline sodium cyclopentadienide directly with the appropriate ketones.

  • 145. Chakka, Sai Kumar
    et al.
    Andersson, Pher G
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Maguire, Glenn E. M.
    Kruger, Hendrik G.
    Govender, Thavendran
    Synthesis and Screening of C-1-Substituted Tetrahydroisoquinoline Derivatives for Asymmetric Transfer Hydrogenation Reactions2010In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 5, p. 972-980Article in journal (Refereed)
    Abstract [en]

    Tetrahydroisoquinoline (TIQ) derivatives exhibit good biological activity. However, utilization of TIQ compounds in asymmetric catalysis is limited. This paper presents a series of TIQ derivatives in asymmetric transfer hydrogenation (ATH) reactions. Chiral TIQ amino alcohol ligands were synthesized and screened for the ATH reaction of aromatic ketones. The effect of a cis- and trans-phenyl substitution at the C-1 position on the ligand backbone was investigated both experimentally and computationally. The results showed that the trans orientation on the TIQ scaffold yields higher turnover rates with a selectivity of 94% ee obtained at room temperature with an Ru complex. The cis isomer results in a high turnover rate with no selectivity. The trans isomer gave 99% ee at lower temperatures. Furthermore, it was observed that substitution at the C-3-alpha position results in a drop of the enantioselectivity and the reactivity of the catalyst.

  • 146. Chakka, Sai Kumar
    et al.
    Peters, Byron K.
    Andersson, Pher G
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Maguire, Glenn E. M.
    Kruger, Hendrik G.
    Govender, Thavendran
    Iridium-catalyzed asymmetric hydrogenation of olefins using TIQ phosphine-oxazoline ligands2010In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 18, p. 2295-2301Article in journal (Refereed)
    Abstract [en]

    A novel family of tetrahydroisoquinoline (TIQ) phosphine-oxazoline ligands and four corresponding iridium complexes have been developed and applied to the asymmetric hydrogenation of unfunctionalized olefins. The results showed that the best conversion rates were observed in up to 99% with an enantiomeric excess of 91%.

  • 147.
    Chatterjee, S.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Pathmasiri, W.
    Plashkevych, O.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Honcharenko, D.
    Varghese, O.P.
    Maiti, M.
    Chattopadhyaya, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    The chemical nature of the 2'-substituent in the pentose-sugar dictates the pseudoaromatic character of the nucleobase (pKa) in DNA/RNA.2006In: Org. Biomol. Chem., Vol. 4, p. 1675-1686Article in journal (Refereed)
    Abstract
  • 148.
    Chatterjee, Subhrangsu
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Physicochemical and Structural Aspects of Nucleic Acids2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis consists of seven research publications concerning (i) pKa studies of nucleobases in model nucleotides to understand why RNA duplexes are more stable than DNA duplexes (Paper I), (ii) the role of Me(T)-π interactions in the relative stability of DNA-RNA heteroduplexes (Paper II), (iii) pKa measurements in nucleotides with different 2′-substituents (paper III), (iv) a conformation study of constrained sugars and a pKa study of 1-thyminyl to reveal effect of sugar constraints on the pKa of the nucleobase (paper IV), (v) NMR and MD studies of 1′, 2′-oxetane constrained thymidine incorporated Dickerson Drew dodecamer (paper V), (vi) the sequence dependent pKa perturbation of 9-guaninyl moeity in single stranded (ss) DNA and RNA (paper VI), (vii) the non identical chemical nature of internucleotidic phosphates in (ss) RNA using 31P NMR (paper VI), and an alkaline hydrolysis study of phosphodiesters in ssRNAs (paper VII). The architecture of DNA and RNA molecules is determined by (a) hydrogen bonding (b) base stacking (c) a variety of additional non-covalent interactions. In paper (I) we showed that A-U and G-C base pairings in RNA are more stable than A-T and G-C base pairings in DNA by 4.3 and 1 kJ mol-1 respectively. Me(T)-π interaction plays a dominant role in the relative stability of DNA-RNA duplexes (paper II). In paper III and IV, we have shown that 1′ , 2′- oxetane and azetidine rings have strong inductive effect on pyrimidine bases, and that the H2′-sugar proton can be the marker to understand the pseudoaromaticity of pyrimidine bases, as well as increasing constraints in sugar reducing the basicity of nucleobases. A 1′, 2′-oxetane locked thymidine (T) moiety deforms the local structure of Dickerson-Drew dodecamer, d(CGCGAATTCGCG)2- investigated by High resolution NMR and MD study, as is discussed in the paper V. In papers VI and VII, we showed sequence context dependent pKa (N1) of 9-guaninyl perturbation in (ss) DNAs and RNAs and the non identical chemical nature of inter-nucleotidic phosphate groups in single stranded RNAs.

    List of papers
    1. Measurement of nucleobase pKa values in model mononucleotides shows RNA-RNA duplexes to be more stable than DNA-DNA duplexes
    Open this publication in new window or tab >>Measurement of nucleobase pKa values in model mononucleotides shows RNA-RNA duplexes to be more stable than DNA-DNA duplexes
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    2004 In: J. Am. Chem. Soc., Vol. 126, p. 2862-2869Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-96570 (URN)