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Proton‐Coupled Reduction of the Catalytic [4Fe‐4S] Cluster in [FeFe]‐Hydrogenases
Author(s) -
Senger Moritz,
Laun Konstantin,
Wittkamp Florian,
Duan Jifu,
Haumann Michael,
Happe Thomas,
Winkler Martin,
Apfel UlfPeter,
Stripp Sven T.
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201709910
Subject(s) - hydrogenase , chemistry , overpotential , catalysis , photochemistry , electrochemistry , electron transport chain , biocatalysis , hydrogen , cluster (spacecraft) , cofactor , combinatorial chemistry , reaction mechanism , enzyme , electrode , organic chemistry , biochemistry , computer science , programming language
In nature, [FeFe]‐hydrogenases catalyze the uptake and release of molecular hydrogen (H 2 ) at a unique iron‐sulfur cofactor. The absence of an electrochemical overpotential in the H 2 release reaction makes [FeFe]‐hydrogenases a prime example of efficient biocatalysis. However, the molecular details of hydrogen turnover are not yet fully understood. Herein, we characterize the initial one‐electron reduction of [FeFe]‐hydrogenases by infrared spectroscopy and electrochemistry and present evidence for proton‐coupled electron transport during the formation of the reduced state Hred′. Charge compensation stabilizes the excess electron at the [4Fe‐4S] cluster and maintains a conservative configuration of the diiron site. The role of Hred′ in hydrogen turnover and possible implications on the catalytic mechanism are discussed. We propose that regulation of the electronic properties in the periphery of metal cofactors is key to orchestrating multielectron processes.