Lyu Zhi Xin, Zhao Xin Sheng
*Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Department of Chemical Biology, College of Chemistry and Molecular Engineering, and Biodynamic Optical Imaging Center (BIOPIC), Peking University, Beijing 100871, China.
Biochem Soc Trans. 2015 Apr;43(2):133-8. doi: 10.1042/BST20140217.
The β-barrel outer membrane proteins (OMPs) are integral membrane proteins that reside in the outer membrane of Gram-negative bacteria and perform a diverse range of biological functions. Synthesized in the cytoplasm, OMPs must be transported across the inner membrane and through the periplasmic space before they are assembled in the outer membrane. In Escherichia coli, Skp, SurA and DegP are the most prominent factors identified to guide OMPs across the periplasm and to play the role of quality control. Although extensive genetic and biochemical analyses have revealed many basic functions of these periplasmic proteins, the mechanism of their collaboration in assisting the folding and insertion of OMPs is much less understood. Recently, biophysical approaches have shed light on the identification of the intricate network. In the present review, we summarize recent advances in the characterization of these key factors, with a special emphasis on the multifunctional protein DegP. In addition, we present our proposed model on the periplasmic quality control in biogenesis of OMPs.
β-桶状外膜蛋白（OMPs）是整合膜蛋白，存在于革兰氏阴性菌的外膜中，执行多种生物学功能。OMPs在细胞质中合成，在组装到外膜之前，必须穿过内膜并通过周质空间。在大肠杆菌中，Skp、SurA和DegP是已确定的引导OMPs穿过周质并发挥质量控制作用的最主要因子。尽管广泛的遗传和生化分析揭示了这些周质蛋白的许多基本功能，但它们在协助OMPs折叠和插入过程中的协作机制却知之甚少。最近，生物物理方法为识别这个复杂网络提供了线索。在本综述中，我们总结了这些关键因子表征方面的最新进展，特别强调了多功能蛋白DegP。此外，我们还提出了关于OMPs生物合成过程中周质质量控制的模型。
