3sps

Publication Abstract from PubMed

Acyl-coenzyme A (acyl-CoA) thioesterases play a crucial role in the metabolism of activated fatty acids, coenzyme A, and other metabolic precursor molecules including arachidonic acid and palmitic acid. These enzymes hydrolyze coenzyme A from acyl-CoA esters to mediate a range of cellular functions including beta-oxidation, lipid biosynthesis, and signal transduction. Here, we present the crystal structure of a hexameric hot-dog domain-containing acyl-CoA thioesterase from Bacillus halodurans in the apo-form and provide structural and comparative analyses to the coenzyme A-bound form to identify key conformational changes induced upon ligand binding. We observed dramatic ligand-induced changes at both the hot-dog dimer and the trimer-of-dimer interfaces; the dimer interfaces in the apo-structure differ by over 20% and decrease to about half the size in the ligand-bound state. We also assessed the specificity of the enzyme against a range of fatty acyl-CoA substrates and have identified a preference for short-chain fatty acyl-CoAs. Coenzyme A was shown both to negatively regulate enzyme activity, representing a direct inhibitory feedback, and consistent with the structural data, to destabilize the quaternary structure of the enzyme. Coenzyme A-induced conformational changes in the C-terminal helices of enzyme were assessed through mutational analysis and shown to play a role in regulating enzyme activity. The conformational changes are likely to be conserved from bacteria through to humans and provide a greater understanding, particularly at a structural level, of thioesterase function and regulation.

Ligand-induced conformational changes within a hexameric Acyl-CoA thioesterase.,Marfori M, Kobe B, Forwood JK J Biol Chem. 2011 Oct 14;286(41):35643-9. doi: 10.1074/jbc.M111.225953. Epub 2011, Aug 17. PMID:21849495^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.