Lin J J, Wu H C
J Bacteriol. 1976 Mar;125(3):892-904. doi: 10.1128/jb.125.3.892-904.1976.
A glycerol-requiring mutant of Salmonella typhimurium was used in a study of the biosynthesis and assembly of a structural lipoprotein in the cell envelope of gram-negative bacteria. Upon removal of glycerol from the growth medium, the biosynthesis of lipoprotein, as measured by radioactive arginine incorporation, was reduced by the same extent as that of other envelope proteins, the cumulative incorporation of arginine being 20% of that of the unstarved control cells. However, the incorporation of radioactive palmitate into lipoprotein was more severely curtailed after glycerol starvation, the cumulative rate of which was 8% of that observed in the unstarved cells. It was further observed that the lipoprotein synthesized in the glycerol-starved cells was more enriched in unmodified cysteine, which is known to be the N-terminal amino acid of lipoprotein, than that synthesized in the unstarved cells. We conclude that the synthesis of the apoprotein portion of Braun's lipoprotein proceeds independently of the attachment of diglyceride to the sulfhydryl group of the N-terminal cysteine and may, in fact, precede the incorporation of the diglyceride moiety.
鼠伤寒沙门氏菌的一个甘油需求突变体被用于研究革兰氏阴性菌细胞膜中一种结构脂蛋白的生物合成与组装。从生长培养基中去除甘油后，通过放射性精氨酸掺入法测定，脂蛋白的生物合成与其他细胞膜蛋白的生物合成下降幅度相同，精氨酸的累积掺入量为未饥饿对照细胞的20%。然而，甘油饥饿后，放射性棕榈酸掺入脂蛋白的情况受到更严重的抑制，其累积速率为未饥饿细胞中观察到的速率的8%。进一步观察到，在甘油饥饿细胞中合成的脂蛋白比未饥饿细胞中合成的脂蛋白含有更多未修饰的半胱氨酸，已知半胱氨酸是脂蛋白的N端氨基酸。我们得出结论，布劳恩脂蛋白的脱辅基蛋白部分的合成独立于二甘油酯与N端半胱氨酸巯基的连接，实际上可能在二甘油酯部分掺入之前就已发生。
