title: Biochemical and structural basis for inhibition of Enterococcus faecalis hydroxymethylglutaryl-CoA synthase, mvaS, by hymeglusin.
abstract: Hymeglusin (1233A, F244, L-659-699) is established as a specific β-lactone inhibitor of eukaryotic hydroxymethylglutaryl-CoA synthase (HMGCS). Inhibition results from formation of a thioester adduct to the active site cysteine. In contrast, the effects of hymeglusin on bacterial HMG-CoA synthase, mvaS, have been minimally characterized. Hymeglusin blocks growth of Enterococcus faecalis. After removal of the inhibitor from culture media, a growth curve inflection point at 3.1 h is observed (vs 0.7 h for the uninhibited control). Upon hymeglusin inactivation of purified E. faecalis mvaS, the thioester adduct is more stable than that measured for human HMGCS. Hydroxylamine cleaves the thioester adduct; substantial enzyme activity is restored at a rate that is 8-fold faster for human HMGCS than for mvaS. Structural results explain these differences in enzyme-inhibitor thioester adduct stability and solvent accessibility. The E. faecalis mvaS-hymeglusin cocrystal structure (1.95 Å) reveals virtually complete occlusion of the bound inhibitor in a narrow tunnel that is largely sequestered from bulk solvent. In contrast, eukaryotic (Brassica juncea) HMGCS binds hymeglusin in a more solvent-exposed cavity.
authors.affiliation: University of Missouri, Kansas City, MO, USA.
authors.forename: D Andrew
authors.initials: DA
authors.lastname: Skaff
authors.forename: Kasra X
authors.initials: KX
authors.lastname: Ramyar
authors.forename: William J
authors.initials: WJ
authors.lastname: McWhorter
authors.forename: Michael L
authors.initials: ML
authors.lastname: Barta
authors.forename: Brian V
authors.initials: BV
authors.lastname: Geisbrecht
authors.forename: Henry M
authors.initials: HM
authors.lastname: Miziorko
mesh_terms: D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D013293:Enterococcus faecalis / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D019811:Hydroxylamine / Q000737:chemistry / Q000494:pharmacology; D006904:Hydroxymethylglutaryl-CoA Synthase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D007783:Lactones / Q000737:chemistry / Q000494:pharmacology*; D008958:Models, Molecular; D015394:Molecular Structure; D011485:Protein Binding; D014961:X-Ray Diffraction
chemical_list: D004791:Enzyme Inhibitors; D005231:Fatty Acids, Unsaturated; D007783:Lactones; C054282:antibiotic 1233A; D019811:Hydroxylamine; D006904:Hydroxymethylglutaryl-CoA Synthase