Ambroziak Patrycja, Rzepka Iga, Skorko-Glonek Joanna
Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland.
Acta Biochim Pol. 2021 Aug 31;68(3):427-436. doi: 10.18388/abp.2020_5761.
Most bacterial secretory proteins destined to the extracytoplasmic space are secreted posttranslationally by the Sec translocase. SecA, a key component of the Sec system, is the ATPase motor protein, directly responsible for transferring the preprotein across the cytoplasmic membrane. SecA is a large protein, composed of several domains, capable of binding client preproteins and a variety of partners, including the SecYEG inner membrane channel complex, membrane phospholipids and ribosomes. SecA-mediated translocation can be divided into two major steps: (1) targeting of the preproteins to the membrane translocation apparatus and (2) transport across the membrane through the SecYEG channel. In this review we present current knowledge regarding SecA structure and function of this protein in both translocation steps. The most recent model of the SecA-dependent preprotein mechanical translocation across the bacterial cytoplasmic membrane is described. A possibility of targeting SecA with inhibitory compounds as a strategy to combat pathogenic bacteria will be discussed as well.
大多数定位于细胞外空间的细菌分泌蛋白是通过Sec转位酶在翻译后分泌的。SecA是Sec系统的关键组成部分，是一种ATP酶运动蛋白，直接负责将前体蛋白转运穿过细胞质膜。SecA是一种大型蛋白质，由多个结构域组成，能够结合客户前体蛋白和多种伙伴，包括SecYEG内膜通道复合物、膜磷脂和核糖体。SecA介导的转位可分为两个主要步骤：（1）将前体蛋白靶向膜转位装置；（2）通过SecYEG通道跨膜运输。在这篇综述中，我们介绍了关于SecA在这两个转位步骤中的结构和功能的当前知识。描述了SecA依赖性前体蛋白跨细菌细胞质膜机械转位的最新模型。还将讨论用抑制性化合物靶向SecA作为对抗病原菌策略的可能性。
