Sidén I, Boman H G
J Bacteriol. 1983 Apr;154(1):170-6. doi: 10.1128/jb.154.1.170-176.1983.
Cecropins are a family of small, basic antibacterial polypeptides which can be isolated from pupae of immunized Lepidoptera. They are active against both gram-negative and gram-positive bacteria. We studied a mutant of Escherichia coli, strain SB1004, which is more sensitive to cecropin D than is the parental strain. The mutant was selected as resistant to a host range mutant of a Serratia marcescens phage. When the protein composition of the outer membrane was examined, strain SB1004 and some other phage-resistant mutants were found to be deficient in the OmpC protein. It was concluded that the OmpC protein is the receptor of the phage. Strain SB1004 was found to differ from other ompC mutants in being especially sensitive to hydrophobic antibiotics and to cecropin D. Furthermore, strain SB1004 has a tendency for spontaneous autolysis. A genetic analysis showed the mutations in strain SB1004 and a suppressor mutant to map in the ompC region. The activity of cecropin D against different strains of E. coli was specifically enhanced when divalent cations were absent. No such effect was found with cecropins A and B, which are less hydrophobic than the D form.
杀菌肽是一类小的碱性抗菌多肽，可从免疫的鳞翅目昆虫蛹中分离得到。它们对革兰氏阴性菌和革兰氏阳性菌均有活性。我们研究了大肠杆菌的一个突变株SB1004，它对杀菌肽D比亲本菌株更敏感。该突变株是作为对粘质沙雷氏菌噬菌体的宿主范围突变体具有抗性而被筛选出来的。当检测外膜的蛋白质组成时，发现SB1004菌株和其他一些噬菌体抗性突变体缺乏OmpC蛋白。由此得出结论，OmpC蛋白是该噬菌体的受体。发现SB1004菌株与其他ompC突变体的不同之处在于它对疏水性抗生素和杀菌肽D特别敏感。此外，SB1004菌株有自发自溶的倾向。遗传分析表明，SB1004菌株和一个抑制突变体中的突变位于ompC区域。当不存在二价阳离子时，杀菌肽D对不同大肠杆菌菌株的活性会特异性增强。对于疏水性比D型弱的杀菌肽A和B，未发现这种效应。
