革兰阳性菌青霉素结合蛋白研究进展

Progress on Penicillin Binding Proteins of Gram-positive Bacteria

革兰阳性菌的青霉素结合蛋白(PBPs)是一类在肽聚糖合成中起着重要作用酶类。聚合过程中存在3种关键的酶类,即糖基转移酶、肽基转移酶和D-丙氨酰-D-丙氨酸羧肽酶(D,D-羧肽酶)。A型高分子质量PBPs是一类双重功能的PBPs,它具有糖基转移酶和肽基转移酶的作用。B型高分子质量PBPs只有肽基转移酶的活性,低分子质量PBPs普遍具有D,D-羧肽酶的活性。PBPs数量和结构的变化均会导致细菌对β-内酰胺类抗生素产生耐药性。不同革兰阳性菌PBPs的数量、种类和功能不尽相同,但在发生β-内酰胺类抗生素耐药时,往往是PBPs相应的基因发生变异,构成了细菌耐药机制中的重要部分。

Penicillin binding proteins（PBPs）of Gram-positive bacteria play a key role in peptidoglycan synthesis, and three enzymes which are glycosyltransferase, peptidyltransferase, and D-alanyl-D-alanine carboxypeptidase are very important in the process of peptidoglycan synthesis. Class A PBPs in high molecular weight have double functions： The N-termini performs a glycosyltransferrase function and the C-termini performs a peptidyltransferase function, while Class B PBPs in high molecular weight only carry the peptidyltransferase activity. The most PBPs in low molecular weight carry a D-alanyl-D-alanine carboxypeptid- ase activity. The quantities, classes and functions of PBPs varies with different Gram-positive bacteria, but it is, in most case, the same gene mutation of PBPs that results in bacteria drug-resistance to β-Lactan antibiotics, which is the main drug-resistance mechanism of bacteria.