Characterization of Methyl- and Acetyl-Ni Intermediates in Acetyl CoA Synthase Formed during Anaerobic CO2 and CO Fixation.
J Am Chem Soc
; 145(25): 13696-13708, 2023 06 28.
Article
in En
| MEDLINE
| ID: mdl-37306669
ABSTRACT
The Wood-Ljungdahl Pathway is a unique biological mechanism of carbon dioxide and carbon monoxide fixation proposed to operate through nickel-based organometallic intermediates. The most unusual steps in this metabolic cycle involve a complex of two distinct nickel-iron-sulfur proteins CO dehydrogenase and acetyl-CoA synthase (CODH/ACS). Here, we describe the nickel-methyl and nickel-acetyl intermediates in ACS completing the characterization of all its proposed organometallic intermediates. A single nickel site (Nip) within the A cluster of ACS undergoes major geometric and redox changes as it transits the planar Nip, tetrahedral Nip-CO and planar Nip-Me and Nip-Ac intermediates. We propose that the Nip intermediates equilibrate among different redox states, driven by an electrochemical-chemical (EC) coupling process, and that geometric changes in the A-cluster linked to large protein conformational changes control entry of CO and the methyl group.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Iron-Sulfur Proteins
/
Nickel
Language:
En
Journal:
J Am Chem Soc
Year:
2023
Document type:
Article
Affiliation country: