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Ligand binding at the A-cluster in full-length or truncated acetyl-CoA synthase studied by X-ray absorption spectroscopy.

ABSTRACT: Bacteria integrate CO2 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 H2O at Ni(I)p in reduced enzyme; a Ni(I)p-CO species was induced by CO incubation and a Ni(II)-CH3- 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.

SUBMITTER: Schrapers P

PROVIDER: S-EPMC5298270 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Ligand binding at the A-cluster in full-length or truncated acetyl-CoA synthase studied by X-ray absorption spectroscopy.

Schrapers Peer P Ilina Julia J Gregg Christina M CM Mebs Stefan S Jeoung Jae-Hun JH Dau Holger H Dobbek Holger H Haumann Michael M

PloS one 20170208 2

Bacteria integrate CO2 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 a ...[more]

PMID: 28178309

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