Sandkvist M, Bagdasarian M, Howard S P
Department of Biochemistry, American Red Cross, Rockville, MD 20855, USA.
Int J Med Microbiol. 2000 Oct;290(4-5):345-50. doi: 10.1016/S1438-4221(00)80038-7.
Vibrio cholerae causes diarrheal disease through colonization of the small intestine. A critical aspect of V. cholerae pathogenesis is its ability to actively secrete cholera toxin to the extracellular environment. This occurs via the type II secretion pathway, where the toxin subunits are first transported to the periplasm through the Sec pathway. Following folding and assembly the toxin is then translocated across the outer membrane by a specialized Extracellular Protein Secretion (Eps) machinery encoded by at least 13 genes. Although the Eps proteins are believed to form a secretion apparatus that spans both membranes, cholera toxin is thought to engage this complex first in the periplasm. In order to determine the organization of the Eps apparatus and to understand the mechanism of secretion, the Eps apparatus has been dissected and three of the components, EpsE, EpsL and EpsM, have been purified and characterized. They were shown to form a stable, multiprotein complex spanning the cytoplasmic membrane.
霍乱弧菌通过在小肠定殖引发腹泻疾病。霍乱弧菌致病机制的一个关键方面是其能够将霍乱毒素主动分泌到细胞外环境中。这是通过II型分泌途径发生的，在该途径中，毒素亚基首先通过Sec途径转运到周质。经过折叠和组装后，毒素随后通过由至少13个基因编码的专门的细胞外蛋白分泌（Eps）机制穿过外膜。尽管Eps蛋白被认为形成了跨越两个膜的分泌装置，但霍乱毒素被认为首先在周质中与这个复合物结合。为了确定Eps装置的组织结构并了解分泌机制，Eps装置已被剖析，其中三个组分EpsE、EpsL和EpsM已被纯化并进行了表征。结果表明它们形成了一个跨越细胞质膜的稳定的多蛋白复合物。
