Lazazzera B A
Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA.
Peptides. 2001 Oct;22(10):1519-27. doi: 10.1016/s0196-9781(01)00488-0.
A novel class of extracellular signaling peptides has been identified in Gram-positive bacteria that are actively transported into the cell to interact with intracellular receptors. The defining members of this novel class of signaling peptides are the Phr peptides of Bacillus subtilis and the mating pheromones of Enterococcus faecalis. These peptides are small and unmodified, gene encoded, and secreted by the bacterium. Most of these peptides diffuse into the extracellular medium, and when their concentration is sufficiently high, they are then actively transported into the cell by an oligopeptide permease (Opp). Once inside the cell, these peptides interact with an array of intracellular receptors. In B. subtilis, the Phr peptides regulate development of environmentally resistant spores and genetically competent cells (i.e. the natural ability to take up exogenous DNA). In E. faecalis, the mating pheromones regulate cell-cell transfer of plasmids, many of which encode antibiotic resistance or virulence factors. At least one component of the signaling pathway for these peptides is conserved in many bacteria, Opp. Opp is a non-specific transporter that transports peptides for use as carbon and nitrogen sources. The possibility that other bacteria could possess similar intracellularly functioning signaling peptides is discussed.
在革兰氏阳性细菌中已鉴定出一类新型的细胞外信号肽，它们被主动转运到细胞内与细胞内受体相互作用。这类新型信号肽的典型成员是枯草芽孢杆菌的Phr肽和粪肠球菌的交配信息素。这些肽小且未修饰，由基因编码并由细菌分泌。大多数这类肽扩散到细胞外介质中，当它们的浓度足够高时，便会通过寡肽通透酶（Opp）被主动转运到细胞内。一旦进入细胞，这些肽就会与一系列细胞内受体相互作用。在枯草芽孢杆菌中，Phr肽调节抗环境孢子和遗传感受态细胞（即摄取外源DNA的天然能力）的发育。在粪肠球菌中，交配信息素调节质粒的细胞间转移，其中许多质粒编码抗生素抗性或毒力因子。这些肽信号通路的至少一个组成部分在许多细菌中是保守的，即Opp。Opp是一种非特异性转运蛋白，可转运肽用作碳源和氮源。文中还讨论了其他细菌可能拥有类似的细胞内起作用的信号肽的可能性。
