InterPro domain: IPR011904

Acetyl-CoA synthetase (also known as acetate-CoA ligase and acetyl-activating enzyme) is a ubiquitous enzyme, found in both prokaryotes and eukaryotes, which catalyses the formation of acetyl-CoA from acetate, coenzyme A (CoA) and ATP as shown below [ 1 ]: ATP + acetate + CoA = AMP + diphosphate + acetyl-CoA The activity of this enzyme is crucial for maintaining the required levels of acetyl-CoA, a key intermediate in many important biosynthetic and catabolic processes. It is especially important in eukayotic species as it is the only route for the activation of acetate to acetyl-CoA in these organisms (some prokaryotic species can also activate acetate by either acetate kinase/phosphotransacetylase or by ADP-forming acetyl-CoA synthase). Eukaryotes typically have two isoforms of acetyl-CoA synthase, a cytosolic form involved in biosynthetic processes and a mitochondrial form primarily involved in energy generation.

The crystal structures of a eukaryotic ( Q01574 , from yeast) and bacterial ( Q8ZKF6 , from Salmonella) form of this enzyme have been determined [ 2 , 3 ]. The yeast enzyme is trimeric, while the bacterial enzyme is monomeric. The trimeric state of the yeast protein may be unique to this organism however, as the residues involved in the trimer interface are poorly conserved in other sequences. Despite differences in the oligomeric state of the two enzyme, the structures of the monomers are almost identical. A large N-terminal domain (~500 residues) containing two parallel beta sheets is followed by a small (~110 residues) C-terminal domain containing a three-stranded beta sheet with helices. The active site occurs at the domain interface, with its contents determining the orientation of the C-terminal domain.

1. Acetyl-coenzyme A synthetase (AMP forming). Cell. Mol. Life Sci. 61, 2020-30
2. Crystal structure of yeast acetyl-coenzyme A synthetase in complex with AMP. Biochemistry 43, 1425-31
3. The 1.75 A crystal structure of acetyl-CoA synthetase bound to adenosine-5'-propylphosphate and coenzyme A. Biochemistry 42, 2866-73