Ligand binding at the A-cluster in full-length or truncated acetyl-CoA synthase studied by X-ray absorption spectroscopy.
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.
Department of Physics, Freie Universität Berlin, Berlin, Germany.
Peer
P
Schrapers
Institute of Biology, Structural Biology/Biochemistry, Humboldt-Universität zu Berlin, Berlin, Germany.
Julia
J
Ilina
Institute of Biology, Structural Biology/Biochemistry, Humboldt-Universität zu Berlin, Berlin, Germany.
Christina M
CM
Gregg
Department of Physics, Freie Universität Berlin, Berlin, Germany.
Stefan
S
Mebs
Institute of Biology, Structural Biology/Biochemistry, Humboldt-Universität zu Berlin, Berlin, Germany.
Jae-Hun
JH
Jeoung
Department of Physics, Freie Universität Berlin, Berlin, Germany.
Holger
H
Dau
Institute of Biology, Structural Biology/Biochemistry, Humboldt-Universität zu Berlin, Berlin, Germany.
Holger
H
Dobbek
Department of Physics, Freie Universität Berlin, Berlin, Germany.
Michael
M
Haumann
D000106:Acetate-CoA Ligase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020134:Catalytic Domain; D008024:Ligands; D008670:Metals / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D009154:Mutation; D011485:Protein Binding; D056928:X-Ray Absorption Spectroscopy
D008024:Ligands; D008670:Metals; D000106:Acetate-CoA Ligase