Type V Secretion in Gram-Negative Bacteria.
Type V Secretion in Gram-Negative Bacteria.
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DOI：
10.1128/ecosalplus.esp-0031-2018
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发表时间：
2019-02-01
期刊：
影响因子：
--
通讯作者：
Bernstein, Harris D
中科院分区：
文献类型：
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作者：
Bernstein, Harris D
V 型分泌或“自转运蛋白”分泌是一个术语，用于指在多种革兰氏阴性细菌中发现的几种简单的蛋白质输出途径。自转运蛋白通常是单一多肽，由胞外（“过客”）结构域和将蛋白质锚定到外膜（OM）的β桶结构域组成。尽管最初提出过客结构域是通过仅由共价连接的 β 桶结构域形成的通道分泌的，但主要在 Va 型或“经典”自转运蛋白途径上进行的实验对这一假设提出了挑战。多项证据强烈表明，过客结构域的分泌和 β 桶结构域的膜整合都是由桶组装机械 (Bam) 复合体催化的，Bam 是一种保守的异源寡聚体，在大多数完整 OM 蛋白的组装中发挥着重要作用。分泌反应似乎至少部分是由细胞外空间中过客结构域的折叠驱动的。尽管自转运蛋白生物发生的许多方面仍有待阐明，但确定属于 V 型标题的不同类别的蛋白质（其中大部分尚未详细检查）是否通过与经典自转运蛋白相同的基本机制组装将特别有趣。
Type V, or "autotransporter," secretion is a term used to refer to several simple protein export pathways that are found in a wide range of Gram-negative bacteria. Autotransporters are generally single polypeptides that consist of an extracellular ("passenger") domain and a beta barrel domain that anchors the protein to the outer membrane (OM). Although it was originally proposed that the passenger domain is secreted through a channel formed solely by the covalently linked beta barrel domain, experiments performed primarily on the type Va, or "classical," autotransporter pathway have challenged this hypothesis. Several lines of evidence strongly suggest that both the secretion of the passenger domain and the membrane integration of the beta barrel domain are catalyzed by the barrel assembly machinery (Bam) complex, a conserved hetero-oligomer that plays an essential role in the assembly of most integral OM proteins. The secretion reaction appears to be driven at least in part by the folding of the passenger domain in the extracellular space. Although many aspects of autotransporter biogenesis remain to be elucidated, it will be especially interesting to determine whether the different classes of proteins that fall under the type V rubric-most of which have not been examined in detail-are assembled by the same basic mechanism as classical autotransporters.