Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, TX, USA.
Adv Exp Med Biol. 2011;715:91-103. doi: 10.1007/978-94-007-0940-9_6.
Pathogenic members of the genus Corynebacterium cause a wide range of serious infections in humans including diphtheria. Adhesion to host cells is a crucial step during infection. In Corynebacterium diphtheriae, adhesion is mediated primarily by filamentous structures called pili or fimbriae that are covalently attached to the bacterial cell wall. C. diphtheriae produces three distinct pilus structures, SpaA-, SpaD- and SpaH-type pili. Similar to other types, the prototype SpaA pilus consists of SpaA forming the pilus shaft and two minor pilins SpaB and SpaC located at the base and at the tip, respectively. The minor pilins SpaB/SpaC are critical for bacterial binding to human pharyngeal cells, and thus represent the major adhesins of corynebacteria. Like pili of many other gram-positive microbes, the assembly of corynebacterial pili occurs by a two-step mechanism, whereby pilins are covalently polymerized by a transpeptidase enzyme named pilin-specific sortase and the generated pilus polymer is subsequently anchored to the cell wall peptidoglycan via the base pilin by the housekeeping sortase or a non-polymerizing sortase. This chapter reviews the current knowledge of corynebacterial adhesion, with a specific focus on pilus structures, their assembly, and the mechanism of adhesion mediated by pili.
棒状杆菌属的致病性成员可引起人类多种严重感染，包括白喉。黏附宿主细胞是感染过程中的关键步骤。在白喉棒状杆菌中，黏附主要通过称为菌毛或纤毛的丝状结构介导，这些结构共价连接到细菌细胞壁上。C. 白喉产生三种不同的菌毛结构，SpaA-、SpaD-和 SpaH-型菌毛。与其他类型类似，原型 SpaA 菌毛由形成菌毛轴的 SpaA 以及分别位于基部和尖端的两个次要菌毛 SpaB 和 SpaC 组成。次要菌毛 SpaB/SpaC 对于细菌与人咽细胞的结合至关重要，因此代表了棒状杆菌的主要黏附素。与许多其他革兰氏阳性微生物的菌毛一样，棒状杆菌菌毛的组装通过两步机制发生，其中菌毛通过称为菌毛特异性分选酶的转肽酶共价聚合，生成的菌毛聚合物通过管家分选酶或非聚合分选酶与细胞壁肽聚糖连接到基底菌毛上。本章综述了关于棒状杆菌黏附的最新知识，特别关注菌毛结构、它们的组装以及菌毛介导的黏附机制。
