Biochemical and structural basis for inhibition of Enterococcus faecalis hydroxymethylglutaryl-CoA synthase, mvaS, by hymeglusin.
Biochemical and structural basis for inhibition of Enterococcus faecalis hydroxymethylglutaryl-CoA synthase, mvaS, by hymeglusin.
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DOI：
10.1021/bi300037k
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发表时间：
2012-06-12
期刊：
影响因子：
2.9
通讯作者：
Miziorko HM
中科院分区：
文献类型：
--
作者：
Skaff DA;Ramyar KX;McWhorter WJ;Barta ML;Geisbrecht BV;Miziorko HM
Hymeglusin(1233A；F244；L-659-699)是真核生物羟甲基戊二酰辅酶A合成酶的特异性β-内酯抑制剂。抑制作用是由于活性部位半胱氨酸形成硫酸酯加合物所致。相比之下，Hymeglusin对细菌HMG-CoA合成酶MVAS的影响还没有得到最小的表征。Hymeglusin可抑制粪肠球菌的生长。从培养液中去除抑制剂后，观察到生长曲线拐点出现在3.1小时(未加抑制的对照为0.7小时)。在纯化的粪肠球菌MVAS灭活膜球蛋白后，硫酯加合物比人HMGCS更稳定。羟胺裂解硫酯加合物；人类HMGCS恢复酶活性的速度是MVAS的8倍。结构结果解释了酶抑制剂硫酯加合物稳定性/溶剂可及性方面的这些差异。粪肠球菌MVAS-Hymeglusin共晶结构(1.95ä)显示，在一个狭窄的隧道中，结合的缓蚀剂几乎完全被封闭，基本上被主体溶剂封闭。相反，真核生物(Brassica Ciea)HMGCS在更多的溶剂暴露的空腔中结合Hymeglusin。
Hymeglusin (1233A; F244; L-659-699) is established as a specific beta lactone inhibitor of eukaryotic hydroxymethylglutaryl-CoA synthase (HMGCS). Inhibition results from formation of a thioester adduct to the active site cysteine. In contrast, hymeglusin’s effects on bacterial HMG-CoA synthase, mvaS, have been minimally characterized. Hymeglusin blocks growth of Enterococcus faecalis. After removal of inhibitor from culture media, a growth curve inflection point at 3.1 hr is observed (versus 0.7 hr for 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/solvent accessibility. The E. faecalis mvaS-hymeglusin co-crystal structure (1.95 Å) reveals virtually complete occlusion of bound inhibitor in a narrow tunnel that is largely occluded from bulk solvent. In contrast, eukaryotic (Brassica juncea) HMGCS binds hymeglusin in a more solvent exposed cavity.