Fontana R, Canepari P, Satta G, Coyette J
Nature. 1980 Sep 4;287(5777):70-2. doi: 10.1038/287070a0.
The mode of bacterial killing by penicillins is still unknown in spite of many studies on the subject. The recent finding of multiple penicillin binding proteins (PBPs) in sensitive bacteria and the possibility of analysing the binding of the antibiotic to exponentially growing cells have provided new directions for investigating this problem. Sensitivity to lethal and other effects of penicillin varies very significantly with the conditions of growth of the cells. If PBPs were the penicillin target, changes in conditions of growth causing variations in penicillin sensitivity should be accompanied by changes in these proteins. Furthermore, if one of PBPs could be identified as the killing target, it could possibly be demonstrated to show changes in cells growing in different conditions. We show here that in Streptococcus faecalis ATCC 9790 changes in conditions of growth are accompanied by changes in PBPs. Furthermore, in the presence of the minimal dose of 14C-benzylpenicillin causing complete inhibition of cell growth, 100% of the total radioactivity is bound to a single protein (PBP 3).
尽管针对青霉素杀菌模式已有诸多研究，但该模式仍不明晰。近期在敏感细菌中发现了多种青霉素结合蛋白（PBPs），且有可能分析抗生素与指数生长期细胞的结合情况，这为研究此问题提供了新方向。细胞对青霉素致死及其他效应的敏感性会因细胞生长条件的不同而有显著差异。如果PBPs是青霉素的作用靶点，那么导致青霉素敏感性变化的生长条件改变应伴随着这些蛋白质的变化。此外，如果能确定其中一种PBPs为杀菌靶点，那么有可能证明其在不同生长条件下的细胞中会出现变化。我们在此表明，在粪肠球菌ATCC 9790中，生长条件的变化伴随着PBPs的变化。此外，在存在导致细胞生长完全抑制的最低剂量14C - 苄青霉素时，总放射性的100%与单一蛋白质（PBP 3）结合。
