Chambers H F, Hartman B J, Tomasz A
J Clin Invest. 1985 Jul;76(1):325-31. doi: 10.1172/JCI111965.
In addition to the four typical penicillin-binding proteins (PBPs), a strain of heterogeneously methicillin-resistant Staphylococcus aureus produced an extra 78-kD PBP (PBP 2a) that had a low affinity for nafcillin and penicillin. Addition of nafcillin to cultures of this strain caused a rapid increase in the amount of this PBP in cell membranes. This increase occurred at subinhibitory concentrations of drug within minutes of exposure, and was blocked by inhibitors of protein and RNA synthesis. This suggests that the synthesis of PBP 2a can be stimulated by exposure to beta-lactam antibiotics. This process may, in part, explain the heterogeneity in methicillin-resistant S. aureus.
除了四种典型的青霉素结合蛋白（PBPs）外，一株异质性耐甲氧西林金黄色葡萄球菌还产生了一种额外的78-kD青霉素结合蛋白（PBP 2a），它对萘夫西林和青霉素的亲和力较低。向该菌株的培养物中添加萘夫西林会导致细胞膜中这种PBP的量迅速增加。这种增加在药物的亚抑制浓度下，暴露几分钟内就会出现，并被蛋白质和RNA合成抑制剂所阻断。这表明暴露于β-内酰胺抗生素可刺激PBP 2a的合成。这一过程可能部分解释了耐甲氧西林金黄色葡萄球菌的异质性。
