Molecular Biology Institute, University of California, Los Angeles, CA, USA.
Department of Medicine, Neag Comprehensive Cancer Center, University of Connecticut Health Center, Farmington, CT, USA.
Trends Microbiol. 2020 Dec;28(12):999-1009. doi: 10.1016/j.tim.2020.05.008. Epub 2020 Jun 1.
Adhesive pili in Gram-positive bacteria represent a variety of extracellular multiprotein polymers that mediate bacterial colonization of specific host tissues and associated pathogenesis. Pili are assembled in two distinct but coupled steps, an orderly crosslinking of pilin monomers and subsequent anchoring of the polymer to peptidoglycan, catalyzed by two transpeptidase enzymes - the pilus-specific sortase and the housekeeping sortase. Here, we review this biphasic assembly mechanism based on studies of two prototypical models, the heterotrimeric pili in Corynebacterium diphtheriae and the heterodimeric pili in Actinomyces oris, highlighting some newly emerged basic paradigms. The disparate mechanisms of protein ligation mediated by the pilus-specific sortase and the spatial positioning of adhesive pili on the cell surface modulated by the housekeeping sortase are among the notable highlights.
革兰氏阳性菌的黏附菌毛代表了多种细胞外多蛋白聚合物，介导了细菌对特定宿主组织的定植和相关发病机制。菌毛由两个不同但偶联的步骤组装而成，即 Pilin 单体的有序交联和随后由两个转肽酶 - 菌毛特异性的 SrtA 和管家 SrtA 催化的聚合物与肽聚糖的锚定。在这里，我们根据两个典型模型（白喉棒状杆菌中的三聚体菌毛和口腔放线菌中的异二聚体菌毛）的研究，综述了这种双相组装机制，强调了一些新出现的基本范例。由菌毛特异性 SrtA 介导的蛋白连接的不同机制和由管家 SrtA 调节的黏附菌毛在细胞表面的空间定位是值得注意的亮点之一。
