Lai J S, Sarvas M, Brammar W J, Neugebauer K, Wu H C
Proc Natl Acad Sci U S A. 1981 Jun;78(6):3506-10. doi: 10.1073/pnas.78.6.3506.
DNA sequence analysis of the structural gene for Bacillus licheniformis penicillinase has revealed a tetrapeptide sequence of Leu-Ala-Gly-Cys within the NH2-terminal part of the precursor form of penicillinase (penicillin amido-beta-lactamhydrolase, EC 3.5.2.6). The same tetrapeptide occurs in the signal sequence of the prolipoprotein of Escherichia coli, and the cysteine residue in the tetrapeptide of prolipoprotein is modified to form glyceride-cysteine which becomes the NH2 terminus of Braun's lipoprotein. On the basis of labeling, with [2-3H]glycerol, [3H]palmitate, [35S]methionine, and [35S]sulfuric acid, of an E. coli strain lysogenic for a lambda vector containing the penicillinase gene from B. licheniformis and of immunoprecipitation with rabbit antisera against purified B. licheniformis penicillinase, we conclude that B. licheniformis penicillinase synthesized in E. coli contains covalently linked glyceride and fatty acid. These results strongly suggest the operation of a modification system in E. coli, and presumably in other Gram-negative bacteria, which results in the formation of a glyceride-cysteine residue if the proper peptide sequence is present in the signal sequence of membrane proteins.
地衣芽孢杆菌青霉素酶结构基因的DNA序列分析表明，在青霉素酶前体形式（青霉素酰胺-β-内酰胺水解酶，EC 3.5.2.6）的NH2末端部分存在一个Leu-Ala-Gly-Cys四肽序列。相同的四肽存在于大肠杆菌前脂蛋白的信号序列中，前脂蛋白四肽中的半胱氨酸残基被修饰形成甘油半胱氨酸，它成为布劳恩脂蛋白的NH2末端。基于用[2-3H]甘油、[3H]棕榈酸、[35S]甲硫氨酸和[35S]硫酸对含有地衣芽孢杆菌青霉素酶基因的λ载体溶原性大肠杆菌菌株进行标记，以及用兔抗纯化地衣芽孢杆菌青霉素酶血清进行免疫沉淀，我们得出结论，在大肠杆菌中合成的地衣芽孢杆菌青霉素酶含有共价连接的甘油酯和脂肪酸。这些结果有力地表明，大肠杆菌中存在一种修饰系统，推测其他革兰氏阴性细菌中也存在，该系统如果膜蛋白信号序列中存在合适的肽序列，就会导致形成甘油半胱氨酸残基。
