Autotransporters are a large and diverse superfamily of proteins produced by pathogenic gram-negative bacteria that are composed of an N-terminal passenger domain, which typically harbors a virulence function, and a C-terminal beta domain. It has long been known that the beta domain anchors the protein to the outer membrane and facilitates transport of the passenger domain into the extracellular space. Despite the apparent simplicity of the autotransporter pathway, several aspects of autotransporter biogenesis remain poorly understood, most notably the mechanism by which the passenger domain is translocated across the outer membrane. Here we review recent evidence that the enormous sequence diversity of both passenger and beta domains belies a remarkable conservation of structure. We also discuss insights into each stage of autotransporter biogenesis that have emerged from recent structural, biochemical, and imaging studies.

中文翻译：

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革兰氏阴性细菌通过自身转运蛋白途径分泌蛋白质。

自转运蛋白是由致病性革兰氏阴性细菌产生的蛋白质的庞大而多样的超家族，其由通常具有毒力功能的N末端过客结构域和C末端β结构域组成。早就知道，β结构域将蛋白质锚定在外膜上，并促进过客结构域转运到细胞外空间。尽管自转运蛋白途径的表面看起来很简单，但是自转运蛋白生物发生的几个方面仍然知之甚少，最值得注意的是过客结构域跨外膜转运的机制。在这里，我们回顾了最近的证据，即乘客和β域的巨大序列多样性掩盖了结构的显着保守性。