Rudnick D A, McWherter C A, Rocque W J, Lennon P J, Getman D P, Gordon J I
Department of Molecular Biology, Washington University School of Medicine, St. Louis, Missouri 63110.
J Biol Chem. 1991 May 25;266(15):9732-9.
The mechanism of catalysis of Escherichia coli-derived Saccharomyces cerevisiae myristoyl-CoA: protein N-myristoyltransferase (NMT) has been characterized. Previous studies indicated that a high affinity reaction intermediate forms between NMT and myristoyl-CoA in the absence of a peptide substrate. This complex has been further characterized using S-(2-oxo)pentadecyl-CoA, a nonhydrolyzable myristoyl-CoA analog. Binding studies involving this analog, as well as myristoylpeptide and CoA, have indicated that the CoA moiety of the acyl substrate is retained in the acyl-NMT complex prior to peptide addition. These structural data, along with kinetic studies of myristoylpeptide and CoA product inhibition, indicate that the mechanism of catalysis of NMT is ordered Bi Bi, with myristoyl-CoA binding to NMT occurring prior to peptide binding and CoA release taking place before release of acyl peptide. Further analyses of the interactions between NMT, acyl peptide, and CoA demonstrate that NMT is able to deacylate a myristoylpeptide in the presence of CoA.
已对源自大肠杆菌的酿酒酵母肉豆蔻酰辅酶A：蛋白质N-肉豆蔻酰转移酶（NMT）的催化机制进行了表征。先前的研究表明，在没有肽底物的情况下，NMT与肉豆蔻酰辅酶A之间会形成高亲和力反应中间体。已使用S-（2-氧代）十五烷基辅酶A（一种不可水解的肉豆蔻酰辅酶A类似物）对该复合物进行了进一步表征。涉及该类似物以及肉豆蔻酰肽和辅酶A的结合研究表明，在添加肽之前，酰基底物的辅酶A部分保留在酰基-NMT复合物中。这些结构数据，连同肉豆蔻酰肽和辅酶A产物抑制的动力学研究，表明NMT的催化机制是有序的双双反应，肉豆蔻酰辅酶A在肽结合之前与NMT结合，辅酶A在酰基肽释放之前释放。对NMT、酰基肽和辅酶A之间相互作用的进一步分析表明，NMT能够在辅酶A存在下使肉豆蔻酰肽脱酰基。
