Cyanide Binding to [FeFe]-Hydrogenase Stabilizes the Alternative Configuration of the Proton Transfer Pathway.
Angew Chem Int Ed Engl
; 62(7): e202216903, 2023 02 06.
Article
em En
| MEDLINE
| ID: mdl-36464641
ABSTRACT
Hydrogenases are H2 converting enzymes that harbor catalytic cofactors in which iron (Fe) ions are coordinated by biologically unusual carbon monoxide (CO) and cyanide (CN- ) ligands. Extrinsic CO and CN- , however, inhibit hydrogenases. The mechanism by which CN- binds to [FeFe]-hydrogenases is not known. Here, we obtained crystal structures of the CN- -treated [FeFe]-hydrogenase CpI from Clostridium pasteurianum. The high resolution of 1.39â
Å allowed us to distinguish intrinsic CN- and CO ligands and to show that extrinsic CN- binds to the open coordination site of the cofactor where CO is known to bind. In contrast to other inhibitors, CN- treated crystals show conformational changes of conserved residues within the proton transfer pathway which could allow a direct proton transfer between E279 and S319. This configuration has been proposed to be vital for efficient proton transfer, but has never been observed structurally.
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Base de dados:
MEDLINE
Assunto principal:
Hidrogenase
/
Proteínas Ferro-Enxofre
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article