Statistical analyses of the oxidized P-clusters in MoFe proteins using the bond-valence method: towards their electron transfer in nitrogenases.
Acta Crystallogr D Struct Biol
; 79(Pt 5): 401-408, 2023 May 01.
Article
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| MEDLINE
| ID: mdl-37071394
ABSTRACT
26 well selected oxidized P-clusters (P2+) from the crystallographic data deposited in the Protein Data Bank have been analysed statistically by the bond-valence sum method with weighting schemes for MoFe proteins at different resolutions. Interestingly, the oxidation states of P2+ clusters correspond to Fe23+Fe62+ with high electron delocalization, showing the same oxidation states as the resting states of P-clusters (PN) in nitrogenases. The previously uncertain reduction of P2+ to PN clusters by two electrons was assigned as a double protonation of P2+, in which decoordination of the serine residue and the peptide chain of cysteine take place, in MoFe proteins. This is further supported by the obviously shorter α-alkoxy C-O bond (average of 1.398â
Å) in P2+ clusters and longer α-hydroxy C-O bond (average of 1.422â
Å) in PN clusters, while no change is observed in the electronic structures of Fe8S7 Fe atoms in P-clusters. Spatially, the calculations show that Fe3 and Fe6, the most oxidized and most reduced Fe atoms, have the shortest distances of 9.329â
Å from the homocitrate in the FeMo cofactor and 14.947â
Å from the [Fe4S4] cluster, respectively, and may well function as important electron-transport sites.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Azotobacter vinelandii
/
Molibdoferredoxina
Idioma:
En
Revista:
Acta Crystallogr D Struct Biol
Año:
2023
Tipo del documento:
Article