革兰氏阴性细菌β-桶状结构外膜蛋白体外折叠的研究进展

The in vitro refolding of β-barrel outer membrane protein of gram-negative bacteria-A review

摘要:

摘要:除了细胞质膜，革兰氏阴性细菌细胞还有一层组成细胞壁的外膜(Outer Membrane)。膜蛋白是外膜的主要组成成分之一，绝大多数外膜蛋白是由反向平行的β-折叠(β-Strands)通过相邻的氢键结合形成的β-桶状结构蛋白(β-Barrel Proteins)。这些蛋白既可作为通道蛋白、转运蛋白、酶、受体、毒力因子，也可作为结构蛋白发挥稳定外膜的重要作用，它们是否正确折叠并整合到外膜对革兰氏阴性细菌的生存至关重要。大多数外膜蛋白易于重组表达和体外重折叠(in vitro refolding)，并且折叠状态可通过多种方法测定，因此β-桶状结构外膜蛋白被当着模式蛋白来研究各类生物和非生物因子对膜蛋白折叠的影响，是膜蛋白研究的一大热点。本文将从β-桶状结构外膜蛋白体外折叠的研究方法和影响折叠的因素角度对近年相关研究进展进行综合述评，最后总结了外膜蛋白体外折叠模式，并结合作者的相关研究结果和观点对该领域的研究前景进行了展望。

Abstract:

Abstract:A cell of gram-negative bacteria is surrounded by two layers of membrane，the inner membrane and the outer membrane．Proteins are the major composition of outer membrane．Many outer membrane proteins carry a trans-membrane β-barrel structure that formed by multiple anti-parallel β-strands connected with hydrogen bonds．These proteins can act as porins，transporters，enzymes，receptors，virulence factors and structural proteins. Therefore，their correct folding and membrane integration are important for the survival of gram-negative bacteria． Most β-barrel outer membrane proteins could be easily expressed recombinantly and refolded in vitro under certain conditions． The in vitro folding processes could be monitored and investigated through many ways，which makes outer membrane proteins become a model system to study the effects of abiotic and biological factors on the folding of membrane proteins． In this article，the research progress on the in vitro refolding of outer membrane proteins are reviewed from the aspects of refolding methods，the factors that affect folding processes and experimental methods． Finally，the research prospects in this field are discussed.