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- Greco, Claudio, et al.
(författare)
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Structural insights into the active-ready form of [FeFe]-Hydrogenase and mechanistic details of its inhibition by carbon monoxide
- 2007
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 1520-510X .- 0020-1669. ; 46:18, s. 7256-7258
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Tidskriftsartikel (refereegranskat)abstract
- [FeFe]-Hydrogenases harbor a {2Fe3S} assembly bearing two CO and two CN- groups, a mu-CO ligand, and a vacant coordination site trans to the mu-CO group. Recent theoretical results obtained studying the isolated {2Fe3S} subsite indicated that one of the CN- ligands can easily move from the crystallographic position to the coordination site trans to the mu-CO group; such an isomerization would have a major impact on substrates and inhibitors binding regiochemistry and, consequently, on the catalytic mechanism. To shed light on this crucial issue, we have carried out hybrid QM/MM and free energy perturbation calculations on the whole enzyme, which demonstrate that the protein environment plays a crucial role and maintains the CN- group fixed in the position observed in the crystal structure; these results strongly support the hypothesis that the vacant coordination site trans to the mu-CO group has a crucial functional relevance both in the context of CO-mediated inhibition of the enzyme and in dihydrogen oxidation/evolution catalysis.
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