DOI: 10.1073/pnas.2007090117
论文题名: The roles of long-range proton-coupled electron transfer in the directionality and efficiency of [FeFe]-hydrogenases
作者: Lampret O. ; Duan J. ; Hofmann E. ; Winkler M. ; Armstrong F.A. ; Happe T.
刊名: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
出版年: 2020
卷: 117, 期: 34 起始页码: 20520
结束页码: 20529
语种: 英语
英文关键词: Catalyst
; Electrocatalysis
; Hydrogenase
; Proton-coupled electron transfer
; Redox enzymes
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
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. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/163410
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
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]. Proceedings of the National Academy of Sciences of the United States of America,2020-01-01,117(34)