Bierbaum G, Sahl H G
Arch Microbiol. 1985 Apr;141(3):249-54. doi: 10.1007/BF00408067.
Pep 5 and nisin are cationic bactericidal peptides which were shown to induce autolysis in Staphylococcus cohnii 22. In contrast to nisin, Pep 5 induced lysis could be stimulated in the presence of glucose. Addition of lipoteichoic acids (LTA) (D-alanine:phosphorus = 0.475:1) inhibited all effects of Pep 5 on susceptible cells in a molar ratio LTA:Pep 5 of 10:1. Treatment of S. cohnii 22 with Pep 5 or nisin for 20 min and subsequent washing with 2.5 M NaCl released autolysin activity. Crude preparations of the hydrolyzing enzymes produced free amino groups as well as polysaccharide fragments from the murein backbone, suggesting the presence of a muramidase or glucosamidase, and endopeptidase or amidase. Both enzyme activities were inhibited by lipoteichoic acid; they could be fully reactivated by addition of Pep 5 in sufficient concentrations. The velocity of hydrolysis was not influenced by nisin, whereas it was doubled in presence of Pep 5. The results are discussed in view of a possible mechanism of induction of lysis by Pep 5 and nisin.
Pep 5和乳链菌肽是阳离子杀菌肽，已证明它们能诱导科氏葡萄球菌22发生自溶。与乳链菌肽不同，在葡萄糖存在的情况下，Pep 5诱导的裂解作用会增强。添加脂磷壁酸（LTA）（D-丙氨酸：磷 = 0.475:1），以10:1的LTA:Pep 5摩尔比抑制了Pep 5对敏感细胞的所有作用。用Pep 5或乳链菌肽处理科氏葡萄球菌22 20分钟，随后用2.5 M NaCl洗涤，释放出自溶素活性。水解酶的粗制品从胞壁质主链产生了游离氨基以及多糖片段，这表明存在一种溶菌酶或葡糖胺酶，以及内肽酶或酰胺酶。两种酶的活性均受到脂磷壁酸的抑制；通过添加足够浓度的Pep 5，它们可以完全重新激活。水解速度不受乳链菌肽的影响，而在Pep 5存在的情况下，水解速度会加倍。鉴于Pep 5和乳链菌肽诱导裂解的可能机制，对结果进行了讨论。
