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Title: Identification of a catalytic iron-hydride at the H-cluster of [FeFe]-hydrogenase

Journal Article · · Journal of the American Chemical Society
DOI:https://doi.org/10.1021/jacs.6b11409· OSTI ID:1340645

Hydrogenases couple electrochemical potential to the reversible chemical transformation of H2 and protons, yet the reaction mechanism and composition of intermediates are not fully understood. In this Communication we describe the biophysical properties of a hydride-bound state (Hhyd) of the [FeFe]-hydrogenase from Chlamydomonas reinhardtii. The catalytic H-cluster of [FeFe]-hydrogenase consists of a [4Fe-4S] subcluster ([4Fe-4S]H) linked by a cysteine thiol to an azadithiolate-bridged 2Fe subcluster ([2Fe]H) with CO and CN- ligands. Mossbauer analysis and density functional theory (DFT) calculations show that Hhyd consists of a reduced [4Fe-4S]H+ coupled to a diferrous [2Fe]H with a terminally bound Fe-hydride. The existence of the Fe-hydride in Hhyd was demonstrated by an unusually low Mossbauer isomer shift of the distal Fe of the [2Fe]H subcluster. As a result, a DFT model of Hhyd shows that the Fe-hydride is part of a H-bonding network with the nearby bridging azadithiolate to facilitate fast proton exchange and catalytic turnover.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC36-08GO28308
OSTI ID:
1340645
Report Number(s):
NREL/JA-2700-67578
Journal Information:
Journal of the American Chemical Society, Vol. 139, Issue 1; ISSN 0002-7863
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 101 works
Citation information provided by
Web of Science

References (31)

X-ray Crystal Structure of the Fe-Only Hydrogenase (CpI) from Clostridium pasteurianum to 1.8 Angstrom Resolution journal December 1998
Desulfovibrio desulfuricans iron hydrogenase: the structure shows unusual coordination to an active site Fe binuclear center journal January 1999
14N HYSCORE investigation of the H-cluster of [FeFe] hydrogenase: evidence for a nitrogen in the dithiol bridge journal January 2009
Molecular basis of [FeFe]-hydrogenase function journal August 2013
Identification and Characterization of the “Super-Reduced” State of the H-Cluster in [FeFe] Hydrogenase: A New Building Block for the Catalytic Cycle? journal October 2012
EPR and FTIR Analysis of the Mechanism of H 2 Activation by [FeFe]-Hydrogenase HydA1 from Chlamydomonas reinhardtii journal April 2013
Electronic and molecular structures of the active-site H-cluster in [FeFe]-hydrogenase determined by site-selective X-ray spectroscopy and quantum chemical calculations journal January 2014
Hydride Binding to the Active Site of [FeFe]-Hydrogenase journal October 2014
New Redox States Observed in [FeFe] Hydrogenases Reveal Redox Coupling Within the H-Cluster journal July 2014
Vibrational spectroscopy reveals the initial steps of biological hydrogen evolution journal January 2016
A Capable Bridging Ligand for Fe-Only Hydrogenase:  Density Functional Calculations of a Low-Energy Route for Heterolytic Cleavage and Formation of Dihydrogen journal April 2001
Bridging-hydride influence on the electronic structure of an [FeFe] hydrogenase active-site model complex revealed by XAES-DFT journal January 2013
Inaccessibility of the μ-hydride species in [FeFe] hydrogenases journal January 2014
Combining acid–base, redox and substrate binding functionalities to give a complete model for the [FeFe]-hydrogenase journal October 2011
Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides journal June 2016
Investigations on the Role of Proton-Coupled Electron Transfer in Hydrogen Activation by [FeFe]-Hydrogenase journal October 2014
Spectroelectrochemical Characterization of the Active Site of the [FeFe] Hydrogenase HydA1 from Chlamydomonas reinhardtii journal August 2009
All-iron hydrogenase: synthesis, structure and properties of {2Fe3S}-assemblies related to the di-iron sub-site of the H-clusterElectronic supplementary information (ESI) available: crystal and structure refinement data for complexes 4a, 4b and 5a. See http://www.rsc.org/suppdata/dt/b2/b209690k/ journal January 2003
Structural and Spectroscopic Features of Mixed Valent Fe II Fe I Complexes and Factors Related to the Rotated Configuration of Diiron Hydrogenase journal July 2012
EPR/ENDOR, Mössbauer, and Quantum-Chemical Investigations of Diiron Complexes Mimicking the Active Oxidized State of [FeFe]Hydrogenase journal July 2012
Hyperfine interactions and electron distribution in FeIIFeI and FeIFeI models for the active site of the [FeFe] hydrogenases: Mössbauer spectroscopy studies of low-spin FeI journal May 2013
Mössbauer Characterization of the Iron−Sulfur Clusters in Desulfovibrio vulgaris Hydrogenase journal March 2001
Electronic Structure of the H Cluster in [Fe]-Hydrogenases journal September 1999
Modeling the Active Sites in Metalloenzymes. 3. Density Functional Calculations on Models for [Fe]-Hydrogenase:  Structures and Vibrational Frequencies of the Observed Redox Forms and the Reaction Mechanism at the Diiron Active Center journal April 2001
A Density Functional Theory Study on the Active Center of Fe-Only Hydrogenase:  Characterization and Electronic Structure of the Redox States journal May 2002
Targeting Intermediates of [FeFe]-Hydrogenase by CO and CN Vibrational Signatures journal May 2011
Refining the Active Site Structure of Iron−Iron Hydrogenase Using Computational Infrared Spectroscopy journal April 2008
Design and Characterization of Phosphine Iron Hydrides: Toward Hydrogen-Producing Catalysts journal July 2015
Mössbauer and computational investigation of a functional [NiFe] hydrogenase model complex journal January 2015
The active site of the [FeFe]-hydrogenase from Desulfovibrio desulfuricans. II. Redox properties, light sensitivity and CO-ligand exchange as observed by infrared spectroscopy journal December 2005
Heterolytic Cleavage of Hydrogen by an Iron Hydrogenase Model: An Fe-H⋅⋅⋅H-N Dihydrogen Bond Characterized by Neutron Diffraction journal April 2014

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The plasticity of redox cofactors: from metalloenzymes to redox-active DNA journal August 2018
Protonation/reduction dynamics at the [4Fe–4S] cluster of the hydrogen-forming cofactor in [FeFe]-hydrogenases journal January 2018
A [4Fe–4S]-Fe(CO)(CN)-l-cysteine intermediate is the first organometallic precursor in [FeFe] hydrogenase H-cluster bioassembly journal April 2018
A coordinatively saturated nickel complex supported by triazenido ligands: a new electrocatalyst for hydrogen generation via ligand-centered proton-transfer journal January 2017
Crystallographic and spectroscopic assignment of the proton transfer pathway in [FeFe]-hydrogenases journal November 2018
The binuclear cluster of [FeFe] hydrogenase is formed with sulfur donated by cysteine of an [Fe(Cys)(CO) 2 (CN)] organometallic precursor journal September 2019
A [RuRu] Analogue of an [FeFe]-Hydrogenase Traps the Key Hydride Intermediate of the Catalytic Cycle journal March 2018
[FeFe]-Hydrogenases: recent developments and future perspectives journal January 2018
DFT methods applied to answer the question: how accurate is the ligand acidity constant method for estimating the p K a of transition metal hydride complexes MHXL 4 when X is varied? journal January 2018
In Vivo EPR Characterization of Semi-Synthetic [FeFe] Hydrogenases journal February 2018
Chalcogenide substitution in the [2Fe] cluster of [FeFe]-hydrogenases conserves high enzymatic activity journal January 2017
Recent advances in the mechanisms of the hydrogen evolution reaction by non-innocent sulfur-coordinating metal complexes journal January 2020
A [RuRu] Analogue of an [FeFe]-Hydrogenase Traps the Key Hydride Intermediate of the Catalytic Cycle journal March 2018
[FeFe]-Hydrogenases: recent developments and future perspectives text January 2018
1H NMR Spectroscopy of [FeFe] Hydrogenase: Insight into the Electronic Structure of the Active Site journal December 2017
Spectroscopic and Computational Evidence that [FeFe] Hydrogenases Operate Exclusively with CO-Bridged Intermediates journal December 2019