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Structural snapshots for the conformation-dependent catalysis by human medium-chain acyl-coenzyme A synthetase ACSM2A

DOI: 10.1016/j.jmb.2009.03.064 DOI Help
PMID: 19345228 PMID Help

Authors: Grazyna Kochan (University of Oxford) , Ewa Pilka (University of Oxford) , Frank Von Delft (University of Oxford) , Udo Oppermann (University of Oxford) , Wyatt Yue (Oxford University SGC)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Molecular Biology

State: Published (Approved)
Published: May 2009
Diamond Proposal Number(s): 442

Abstract: Acyl-CoA synthetases belong to the superfamily of adenylate-forming enzymes, and catalyze the two-step activation of fatty acids or carboxylate-containing xenobiotics. The carboxylate substrate first reacts with ATP to form an acyl-adenylate intermediate, which then reacts with CoA to produce an acyl-CoA ester. Here, we report the first crystal structure of a medium-chain acyl-CoA synthetase ACSM2A, in a series of substrate/product/cofactor complexes central to the catalytic mechanism. We observed a substantial rearrangement between the N- and C-terminal domains, driven purely by the identity of the bound ligand in the active site. Our structures allowed us to identify the presence or absence of the ATP pyrophosphates as the conformational switch, and elucidated new mechanistic details, including the role of invariant Lys557 and a divalent magnesium ion in coordinating the ATP pyrophosphates, as well as the involvement of a Gly-rich P-loop and the conserved Arg472-Glu365 salt bridge in the domain rearrangement.

Journal Keywords: fatty acid; coenzyme A; adenylation; thioesterification; synthetase

Subject Areas: Biology and Bio-materials

Instruments: I02-Macromolecular Crystallography , I03-Macromolecular Crystallography , I04-Macromolecular Crystallography , I24-Microfocus Macromolecular Crystallography