Journal article
Regioselectivity of H cluster oxidation.
- Bruska MK Laboratorium für Physikalische Chemie, ETH Zurich, Wolfgang-Pauli-Strasse 10 8093 Zürich, Switzerland.
- Stiebritz MT
- Reiher M
- 2011-11-24
Published in:
- Journal of the American Chemical Society. - 2011
English
The H(2)-evolving potential of [FeFe] hydrogenases is severely limited by the oxygen sensitivity of this class of enzymes. Recent experimental studies on hydrogenase from C. reinhardtii point to O(2)-induced structural changes in the [Fe(4)S(4)] subsite of the H cluster. Here, we investigate the mechanistic basis of this observation by means of density functional theory. Unexpectedly, we find that the isolated H cluster shows a pathological catalytic activity for the formation of reactive oxygen species such as O(2)(-) and HO(2)(-). After protonation of O(2)(-), an OOH radical may coordinate to the Fe atoms of the cubane, whereas H(2)O(2) specifically reacts with the S atoms of the cubane-coordinating cysteine residues. Both pathways are accompanied by significant structural distortions that compromise cluster integrity and thus catalytic activity. These results explain the experimental observation that O(2)-induced inhibition is accompanied by distortions of the [Fe(4)S(4)] moiety and account for the irreversibility of this process.
- Language
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- English
- Open access status
- hybrid
- Identifiers
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- DOI 10.1021/ja209165r
- PMID 22106822
- Persistent URL
- https://folia.unifr.ch/global/documents/143325
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