Hydrogenases catalyze the formation of hydrogen. The cofactor ('H-cluster') of [FeFe]-hydrogenases consists of a [4Fe-4S] cluster bridged to a unique [2Fe] subcluster whose biosynthesis in vivo requires hydrogenase-specific maturases. Here we show that a chemical mimic of the [2Fe] subcluster can reconstitute apo-hydrogenase to full activity, independent of helper proteins. The assembled H-cluster is virtually indistinguishable from the native cofactor. This procedure will be a powerful tool for developing new artificial H₂-producing catalysts.
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http://dx.doi.org/10.1038/nchembio.1311 | DOI Listing |
Angew Chem Int Ed Engl
December 2023
Univ. Grenoble-Alpes, CEA, CNRS, IBS, Metalloproteins Unit, 38000, Grenoble, France.
[FeFe]-hydrogenases efficiently catalyze the reversible oxidation of molecular hydrogen. Their prowess stems from the intricate H-cluster, combining a [Fe S ] center with a binuclear iron center ([2Fe] ). In the latter, each iron atom is coordinated by a CO and CN ligand, connected by a CO and an azadithiolate ligand.
View Article and Find Full Text PDFJ Phys Chem B
November 2023
Department of Chemistry, University of California Davis, Davis, California 95616, United States.
[FeFe]-hydrogenases employ a catalytic H-cluster, consisting of a [4Fe-4S] cluster linked to a [2Fe] subcluster with CO, CN ligands, and an azadithiolate bridge, which mediates the rapid redox interconversion of H and H. In the biosynthesis of this H-cluster active site, the radical -adenosyl-l-methionine (radical SAM, RS) enzyme HydG plays the crucial role of generating an organometallic [Fe(II)(CN)(CO)(cysteinate)] product that is en route to forming the H-cluster. Here, we report direct observation of this diamagnetic organometallic Fe(II) complex through Mössbauer spectroscopy, revealing an isomer shift of δ = 0.
View Article and Find Full Text PDFChemSusChem
February 2024
Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany.
[FeFe]-hydrogenases are capable of reducing protons at a high rate. However, molecular oxygen (O ) induces the degradation of their catalytic cofactor, the H-cluster, which consists of a cubane [4Fe4S] subcluster (4Fe ) and a unique diiron moiety (2Fe ). Previous attempts to prevent O -induced damage have focused on enhancing the protein's sieving effect for O by blocking the hydrophobic gas channels that connect the protein surface and the 2Fe .
View Article and Find Full Text PDFJ Am Chem Soc
May 2023
Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States.
[FeFe] hydrogenase from (HydA1) is an unusual hydrogenase in that it can withstand prolonged exposure to O by reversibly converting into an O-protected, inactive state (H). It has been indicated in the past that an atypical conformation of the "SCCP" loop near the [2Fe] portion of the six-iron active site (H-cluster) allows the Cys367 residue to adopt an "off-H-pathway" orientation, promoting a facile transition of the cofactor to H. Here, we investigated the electronic structure of the H-cluster in the oxidized state (H) that directly converts to H under oxidizing conditions and the related CO-inhibited state (H-CO).
View Article and Find Full Text PDF[FeFe] hydrogenases are exceptionally active catalysts for the interconversion of molecular hydrogen with protons and electrons. Their active site, the H-cluster, is composed of a [4Fe-4S] cluster covalently linked to a unique [2Fe] subcluster. These enzymes have been extensively studied to understand how the protein environment tunes the properties of the Fe ions for efficient catalysis.
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