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Esmieu, Charlène
Publications (6 of 6) Show all publications
Aster, A., Wang, S., Mirmohades, M., Esmieu, C., Berggren, G., Hammarström, L. & Lomoth, R. (2019). Metal vs. ligand protonation and the alleged proton-shuttling role of the azadithiolate ligand in catalytic H-2 formation with FeFe hydrogenase model complexes. Chemical Science, 10(21), 5582-5588
Open this publication in new window or tab >>Metal vs. ligand protonation and the alleged proton-shuttling role of the azadithiolate ligand in catalytic H-2 formation with FeFe hydrogenase model complexes
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2019 (English)In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 10, no 21, p. 5582-5588Article in journal (Refereed) Published
Abstract [en]

Electron and proton transfer reactions of diiron complexes [Fe(2)adt(CO)(6)] (1) and [Fe(2)adt(CO)(4)(PMe3)(2)] (4), with the biomimetic azadithiolate (adt) bridging ligand, have been investigated by real-time IR- and UV-vis-spectroscopic observation to elucidate the role of the adt-N as a potential proton shuttle in catalytic H-2 formation. Protonation of the one-electron reduced complex, 1(-), occurs on the adt-N yielding 1H and the same species is obtained by one-electron reduction of 1H(+). The preference for ligand vs. metal protonation in the Fe-2(i,0) state is presumably kinetic but no evidence for tautomerization of 1H to the hydride 1Hy was observed. This shows that the adt ligand does not work as a proton relay in the formation of hydride intermediates in the reduced catalyst. A hydride intermediate 1HHy(+) is formed only by protonation of 1H with stronger acid. Adt protonation results in reduction of the catalyst at much less negative potential, but subsequent protonation of the metal centers is not slowed down, as would be expected according to the decrease in basicity. Thus, the adtH(+) complex retains a high turnover frequency at the lowered overpotential. Instead of proton shuttling, we propose that this gain in catalytic performance compared to the propyldithiolate analogue might be rationalized in terms of lower reorganization energy for hydride formation with bulk acid upon adt protonation.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-390686 (URN)10.1039/c9sc00876d (DOI)000474412700015 ()31293742 (PubMedID)
Funder
Swedish Research Council, 621-2014-5670Swedish Research Council, 2016-04271Swedish Research Council Formas, 213-2014-880
Available from: 2019-08-16 Created: 2019-08-16 Last updated: 2019-08-16Bibliographically approved
Nemeth, B., Esmieu, C., Redman, H. J. & Berggren, G. (2019). Monitoring H-cluster assembly using a semi-synthetic HydF protein. Dalton Transactions, 48(18), 5978-5986
Open this publication in new window or tab >>Monitoring H-cluster assembly using a semi-synthetic HydF protein
2019 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 48, no 18, p. 5978-5986Article in journal (Refereed) Published
Abstract [en]

The [FeFe] hydrogenase enzyme interconverts protons and molecular hydrogen with remarkable efficiency. The reaction is catalysed by a unique metallo-cofactor denoted as the H-cluster containing an organometallic dinuclear Fe component, the [2Fe] subsite. The HydF protein delivers a precursor of the [2Fe] subsite to the apo-[FeFe] hydrogenase, thus completing the H-cluster and activating the enzyme. Herein we generate a semi-synthetic form of HydF by loading it with a synthetic low valent dinuclear Fe complex. We show that this semi-synthetic protein is practically indistinguishable from the native protein, and utilize this form of HydF to explore the mechanism of H-cluster assembly. More specifically, we show that transfer of the precatalyst from HydF to the hydrogenase enzyme results in the release of CO, underscoring that the pre-catalyst is a four CO species when bound to HydF. Moreover, we propose that an electron transfer reaction occurs during H-cluster assembly, resulting in an oxidation of the [2Fe] subsite with concomitant reduction of the [4Fe4S] cluster present on the HydF protein.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2019
National Category
Theoretical Chemistry Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-390520 (URN)10.1039/c8dt04294b (DOI)000472449300013 ()30632592 (PubMedID)
Funder
Swedish Research Council, 621-2014-5670Swedish Research Council Formas, 213-2014-880EU, European Research Council, 714102
Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-09-18Bibliographically approved
Esmieu, C., Raleiras, P. & Berggren, G. (2018). From protein engineering to artificial enzymes - biological and biomimetic approaches towards sustainable hydrogen production. SUSTAINABLE ENERGY & FUELS, 2(4), 724-750
Open this publication in new window or tab >>From protein engineering to artificial enzymes - biological and biomimetic approaches towards sustainable hydrogen production
2018 (English)In: SUSTAINABLE ENERGY & FUELS, ISSN 2398-4902, Vol. 2, no 4, p. 724-750Article, review/survey (Refereed) Published
Abstract [en]

Hydrogen gas is used extensively in industry today and is often put forward as a suitable energy carrier due its high energy density. Currently, the main source of molecular hydrogen is fossil fuels via steam reforming. Consequently, novel production methods are required to improve the sustainability of hydrogen gas for industrial processes, as well as paving the way for its implementation as a future solar fuel. Nature has already developed an elaborate hydrogen economy, where the production and consumption of hydrogen gas is catalysed by hydrogenase enzymes. In this review we summarize efforts on engineering and optimizing these enzymes for biological hydrogen gas production, with an emphasis on their inorganic cofactors. Moreover, we will describe how our understanding of these enzymes has been applied for the preparation of bio-inspired/-mimetic systems for efficient and sustainable hydrogen production.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-357183 (URN)10.1039/c7se00582b (DOI)000428778800002 ()
Funder
Swedish Research Council, 621-2014-5670Swedish Research Council Formas, 213-2014-880EU, European Research Council, 714102
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-13Bibliographically approved
Meszaros, L. S., Nemeth, B., Esmieu, C., Ceccaldi, P. & Berggren, G. (2018). InVivo EPR Characterization of Semi-Synthetic [FeFe] Hydrogenases. Angewandte Chemie International Edition, 57(10), 2596-2599
Open this publication in new window or tab >>InVivo EPR Characterization of Semi-Synthetic [FeFe] Hydrogenases
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2018 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 57, no 10, p. 2596-2599Article in journal (Refereed) Published
Abstract [en]

EPR spectroscopy reveals the formation of two different semi-synthetic hydrogenases invivo. [FeFe] hydrogenases are metalloenzymes that catalyze the interconversion of molecular hydrogen and protons. The reaction is catalyzed by the H-cluster, consisting of a canonical iron-sulfur cluster and an organometallic [2Fe] subsite. It was recently shown that the enzyme can be reconstituted with synthetic cofactors mimicking the composition of the [2Fe] subsite, resulting in semi-synthetic hydrogenases. Herein, we employ EPR spectroscopy to monitor the formation of two such semi-synthetic enzymes in whole cells. The study provides the first spectroscopic characterization of semi-synthetic hydrogenases invivo, and the observation of two different oxidized states of the H-cluster under intracellular conditions. Moreover, these findings underscore how synthetic chemistry can be a powerful tool for manipulation and examination of the hydrogenase enzyme under invivo conditions.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2018
Keywords
[FeFe] hydrogenase, artificial enzymes, EPR spectroscopy, metalloenzymes
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-348975 (URN)10.1002/anie.201710740 (DOI)000426252400010 ()29334424 (PubMedID)
Funder
Swedish Research Council, 21-2014-5670Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning, 213-2014-880EU, European Research Council, 714102
Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2019-09-18Bibliographically approved
Khanna, N., Esmieu, C., Meszaros, L. S., Lindblad, P. & Berggren, G. (2017). In vivo activation of an [FeFe] hydrogenase using synthetic cofactors. Energy & Environmental Science, 10(7), 1563-1567
Open this publication in new window or tab >>In vivo activation of an [FeFe] hydrogenase using synthetic cofactors
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2017 (English)In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 10, no 7, p. 1563-1567Article in journal (Refereed) Published
Abstract [en]

[FeFe] hydrogenases catalyze the reduction of protons, and oxidation of hydrogen gas, with remarkable efficiency. The reaction occurs at the H-cluster, which contains an organometallic [2Fe] subsite. The unique nature of the [2Fe] subsite makes it dependent on a specific set of maturation enzymes for its biosynthesis and incorporation into the apo-enzyme. Herein we report on how this can be circumvented, and the apo-enzyme activated in vivo by synthetic active site analogues taken up by the living cell.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-330015 (URN)10.1039/c7ee00135e (DOI)000405279900003 ()
Funder
Swedish Research Council, 621-2014-5670Swedish Research Council Formas, 213-2014-880Swedish Energy Agency, 11674-5Knut and Alice Wallenberg Foundation, 2011.0067Wenner-Gren Foundations
Note

Correction in: ENERGY & ENVIRONMENTAL SCIENCE, Volume: 11, Issue: 11, Pages: 3321-3321, DOI: 10.1039/c8ee90054j

Available from: 2017-10-11 Created: 2017-10-11 Last updated: 2019-01-17Bibliographically approved
Esmieu, C. & Berggren, G. (2016). Characterization of a monocyanide model of FeFe hydrogenases - highlighting the importance of the bridgehead nitrogen for catalysis. Dalton Transactions, 45(48), 19242-19248
Open this publication in new window or tab >>Characterization of a monocyanide model of FeFe hydrogenases - highlighting the importance of the bridgehead nitrogen for catalysis
2016 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, no 48, p. 19242-19248Article in journal (Refereed) Published
Abstract [en]

An azadithiolate bridged monocyanide derivative [Fe-2(adt)(CO)(5)(CN)](-) of [Fe-2(adt)(CO)(4)(CN)(2)](2-) has been prepared and extensively characterized as a model of the [FeFe]-hydrogenase active site, using a combination of FTIR spectroscopy, electrochemical methods and catalytic assays with chemical reductants. The presence of two basic nitrogen sites opens up multiple protonation pathways, enabling catalytic proton reduction. To our knowledge [Fe-2(adt)(CO)(5)(CN)](-) represents the first example of a cyanide containing [FeFe]-hydrogenase active site mimic capable of catalytic H-2 formation in aqueous media.

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-314063 (URN)10.1039/c6dt02061e (DOI)000390470400010 ()27549900 (PubMedID)
Funder
Swedish Research Council, 621-2014-5670Swedish Research Council Formas, 213-2014-880Wenner-Gren Foundations
Available from: 2017-01-26 Created: 2017-01-26 Last updated: 2017-11-29Bibliographically approved
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