WELBIO, Université catholique de Louvain, avenue Hippocrate 75, Brussels 1200, Belgium.
De Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, Brussels 1200, Belgium.
FEMS Microbiol Lett. 2018 Sep 1;365(18). doi: 10.1093/femsle/fny199.
The discovery of Escherichia coli Lpp as the first protein with three acyl groups covalently attached to its N-terminal cysteine residue defined a new class of bacterial proteins, the lipoproteins. Lipoproteins are extracytoplasmic, globular proteins that are anchored to a membrane by a lipid moiety. Being anchored to the outer membrane, Lpp, which is also known as the Braun lipoprotein, is small (5.8 kDa) and folds into a trimeric helical structure. It is also the numerically most abundant protein in E. coli. A unique feature of Lpp is that its C-terminal lysine residue is covalently attached to the peptidoglycan, providing the only covalent connection between the outer membrane and the cell wall. Here, we review the knowledge gained on Lpp since its discovery in 1969 until the recent finding that Lpp functions as a major size determinant in the bacterial cell envelope. We also discuss the role played by Lpp in virulence and highlight the major questions that remain to be solved.
大肠杆菌 Lpp 作为第一个其 N 端半胱氨酸残基共价连接三个酰基的蛋白质的发现，定义了一类新的细菌蛋白，即脂蛋白。脂蛋白是一种细胞外的球形蛋白，通过脂质部分锚定在膜上。Lpp（也称为 Braun 脂蛋白）与外膜锚定，分子量小（5.8kDa），折叠成三聚体螺旋结构。它也是大肠杆菌中数量最多的蛋白质。Lpp 的一个独特特征是其 C 末端赖氨酸残基与肽聚糖共价连接，为外膜和细胞壁之间提供了唯一的共价连接。在这里，我们回顾了自 1969 年发现 Lpp 以来获得的关于 Lpp 的知识，直到最近发现 Lpp 作为细菌细胞包膜的主要大小决定因素发挥作用。我们还讨论了 Lpp 在毒力中的作用，并强调了仍有待解决的主要问题。
