气候变化领域集成服务门户(CCPortal): The roles of long-range proton-coupled electron transfer in the directionality and efficiency of [FeFe]-hydrogenases

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DOI	10.1073/pnas.2007090117
	The roles of long-range proton-coupled electron transfer in the directionality and efficiency of [FeFe]-hydrogenases
	Lampret O.; Duan J.; Hofmann E.; Winkler M.; Armstrong F.A.; Happe T.
发表日期	2020
ISSN	0027-8424
起始页码	20520
结束页码	20529
卷号	117 期号:34
英文摘要	As paradigms for proton-coupled electron transfer in enzymes and benchmarks for a fully renewable H2 technology, [FeFe]-hydrogenases behave as highly reversible electrocatalysts when immobilized on an electrode, operating in both catalytic directions with minimal overpotential requirement. Using the [FeFe]-hydrogenases from Clostridium pasteurianum (CpI) and Chlamydomonas reinhardtii (CrHydA1) we have conducted site-directed mutagenesis and protein film electrochemistry to determine how efficient catalysis depends on the long-range coupling of electron and proton transfer steps. Importantly, the electron and proton transfer pathways in [FeFe]-hydrogenases are well separated from each other in space. Variants with conservative substitutions (glutamate to aspartate) in either of two positions in the proton-transfer pathway retain significant activity and reveal the consequences of slowing down proton transfer for both catalytic directions over a wide range of pH and potential values. Proton reduction in the variants is impaired mainly by limiting the turnover rate, which drops sharply as the pH is raised, showing that proton capture from bulk solvent becomes critical. In contrast, hydrogen oxidation is affected in two ways: by limiting the turnover rate and by a large overpotential requirement that increases as the pH is raised, consistent with the accumulation of a reduced and protonated intermediate. A unique observation having fundamental significance is made under conditions where the variants still retain sufficient catalytic activity in both directions: An inflection appears as the catalytic current switches direction at the 2H+/H2 thermodynamic potential, clearly signaling a departure from electrocatalytic reversibility as electron and proton transfers begin to be decoupled. © 2020 National Academy of Sciences. All rights reserved.
英文关键词	Catalyst; Electrocatalysis; Hydrogenase; Proton-coupled electron transfer; Redox enzymes
语种	英语
scopus关键词	hydrogenase; oxidoreductase; unclassified drug; [FeFe] hydrogenase; hydrogenase; iron hydrogenase; iron sulfur protein; proton; Article; catalysis; Chlamydomonas reinhardtii; Clostridium pasteurianum; controlled study; electrochemistry; electron transport; mutagenesis; nonhuman; oxidation reduction potential; pH; priority journal; process optimization; proton coupled electron transfer; proton transport; signal transduction; thermodynamics; Clostridium; electron transport; genetics; metabolism; site directed mutagenesis; Chlamydomonas reinhardtii; Clostridium; Electron Transport; Hydrogenase; Iron-Sulfur Proteins; Mutagenesis, Site-Directed; Protons
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160237
作者单位	Lampret, O., Fakultät für Biologie und Biotechnologie, AG Photobiotechnologie, Ruhr-Universität Bochum, Bochum, 44801, Germany; Duan, J., Fakultät für Biologie und Biotechnologie, AG Photobiotechnologie, Ruhr-Universität Bochum, Bochum, 44801, Germany; Hofmann, E., Fakultät für Biologie und Biotechnologie, Proteinkristallographie, Ruhr-Universität Bochum, Bochum, 44801, Germany; Winkler, M., Fakultät für Biologie und Biotechnologie, AG Photobiotechnologie, Ruhr-Universität Bochum, Bochum, 44801, Germany; Armstrong, F.A., Department of Chemistry, University of Oxford, Oxford, OX1 3QR, United Kingdom; Happe, T., Fakultät für Biologie und Biotechnologie, AG Photobiotechnologie, Ruhr-Universität Bochum, Bochum, 44801, Germany
推荐引用方式 GB/T 7714	Lampret O.,Duan J.,Hofmann E.,et al. The roles of long-range proton-coupled electron transfer in the directionality and efficiency of [FeFe]-hydrogenases[J],2020,117(34).
APA	Lampret O.,Duan J.,Hofmann E.,Winkler M.,Armstrong F.A.,&Happe T..(2020).The roles of long-range proton-coupled electron transfer in the directionality and efficiency of [FeFe]-hydrogenases.Proceedings of the National Academy of Sciences of the United States of America,117(34).
MLA	Lampret O.,et al."The roles of long-range proton-coupled electron transfer in the directionality and efficiency of [FeFe]-hydrogenases".Proceedings of the National Academy of Sciences of the United States of America 117.34(2020).