Open AccessLigand binding at the A-cluster in full-length or truncated acetyl-CoA synthase studied by X-ray absorption spectroscopy
Author(s) -
Peer Schrapers,
Julia Ilina,
Christina M. Gregg,
Stefan Mebs,
JaeHun Jeoung,
Holger Dau,
Holger Dobbek,
Michael Haumann
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0171039
Subject(s) - chemistry , ligand (biochemistry) , cluster (spacecraft) , atp synthase , crystallography , enzyme , stereochemistry , spectroscopy , absorption (acoustics) , active site , biochemistry , materials science , receptor , physics , quantum mechanics , computer science , composite material , programming language
Bacteria integrate CO 2 reduction and acetyl coenzyme-A (CoA) synthesis in the Wood-Ljungdal pathway. The acetyl-CoA synthase (ACS) active site is a [4Fe4S]-[NiNi] complex (A-cluster). The dinickel site structure (with proximal, p, and distal, d, ions) was studied by X-ray absorption spectroscopy in ACS variants comprising all three protein domains or only the C-terminal domain with the A-cluster. Both variants showed two square-planar Ni(II) sites and an OH - bound at Ni(II) p in oxidized enzyme and a H 2 O at Ni(I) p in reduced enzyme; a Ni(I) p -CO species was induced by CO incubation and a Ni(II)-CH 3 - species with an additional water ligand by a methyl group donor. These findings render a direct effect of the N-terminal and middle domains on the A-cluster structure unlikely.