Luirink J, Dobberstein B
Department of Microbiology, Biocentrum Amsterdam, The Netherlands.
Mol Microbiol. 1994 Jan;11(1):9-13. doi: 10.1111/j.1365-2958.1994.tb00284.x.
Recent evidence from both biochemical and genetic studies indicates that protein targeting to the prokaryotic cytoplasmic membrane and the eukaryotic endoplasmic reticulum membrane may have more in common than previously thought. A ribonucleoprotein particle was identified in Escherichia coli that consists of at least one protein (P48 or Ffh) and one RNA molecule (4.5S RNA), both of which exhibit strong sequence similarity with constituents of the mammalian signal recognition particle (SRP). Like the mammalian SRP, the E. coli SRP binds specifically to the signal sequence of presecretory proteins. Depletion of either P48 or 4.5S RNA affects translation and results in the accumulation of precursors of several secreted proteins. This review discusses the recent studies and speculates on the position of the SRP in the complex network of protein interactions involved in translation and membrane targeting in E. coli.
来自生化和遗传学研究的最新证据表明，蛋白质靶向原核细胞质膜和真核内质网膜的过程可能比之前认为的有更多共同点。在大肠杆菌中鉴定出一种核糖核蛋白颗粒，它由至少一种蛋白质（P48或Ffh）和一个RNA分子（4.5S RNA）组成，这两者与哺乳动物信号识别颗粒（SRP）的成分都表现出很强的序列相似性。与哺乳动物SRP一样，大肠杆菌SRP特异性结合分泌前体蛋白的信号序列。P48或4.5S RNA的缺失会影响翻译，并导致几种分泌蛋白前体的积累。本文综述了近期的研究，并推测了SRP在大肠杆菌翻译和膜靶向相关复杂蛋白质相互作用网络中的位置。
