Structure of polymerized type V pilin reveals assembly mechanism involving protease-mediated strand exchange
Structure of polymerized type V pilin reveals assembly mechanism involving protease-mediated strand exchange
复制标题
聚合V型菌毛蛋白的结构揭示了涉及蛋白酶介导的链交换的组装机制
DOI：
10.1038/s41564-020-0705-1
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发表时间：
2020
影响因子：
28.3
通讯作者：
Koji Nakayama and Matthias Wolf
中科院分区：
文献类型：
--
作者：
Satoshi Shibata;Mikio Shoji;Kodai Okada;Hideyuki Matsunami;Melissa Matthews;Katsumi Imada;Koji Nakayama and Matthias Wolf
细菌粘附是宿主-微生物和微生物-微生物相互作用的一般策略。粘附性皮利对许多环境和病原菌的定殖、生物膜形成、毒力和致病性至关重要。牙龈卟啉单胞菌（Porphyromonasgingivalis）是牙周病的主要致病菌，其V型皮利是决定其致病力的关键因素。然而，聚合菌毛的结构及其组装机制尚不清楚。在这里，我们显示了聚合和单体状态的FimA茎菌毛蛋白从P。牙龈，通过冷冻电子显微镜和晶体学确定。组装的FimA的原子模型显示，在蛋白酶RgpB的N-末端切割后，供体亚基的C-末端链插入受体亚基的β-折叠中的凹槽中。供体链的C末端对于聚合是必不可少的。我们建议V型皮利组装通过一个顺序的极性组装机制在细胞表面，涉及蛋白酶介导的链交换，采用各种革兰氏阴性菌属于类杆菌。我们的研究结果揭示了与聚合FimA的致病特性相关的功能表面。这些见解可能有助于抗菌药物的开发。
Bacterial adhesion is a general strategy for host–microbe and microbe–microbe interactions. Adhesive pili are essential for colonization, biofilm formation, virulence and pathogenesis of many environmental and pathogenic bacteria,. Members of the class Bacteroidia have unique type V pili, assembled by protease-mediated polymerization.Porphyromonas gingivalisis the main contributor to periodontal disease and its type V pili are a key factor for its virulence. However, the structure of the polymerized pilus and its assembly mechanism are unknown. Here we show structures of polymerized and monomeric states of FimA stalk pilin fromP. gingivalis, determined by cryo-electron microscopy and crystallography. The atomic model of assembled FimA shows that the C-terminal strand of a donor subunit is inserted into a groove in the β-sheet of an acceptor subunit after N-terminal cleavage by the protease RgpB. The C terminus of the donor strand is essential for polymerization. We propose that type V pili assemble via a sequential polar assembly mechanism at the cell surface, involving protease-mediated strand exchange, employed by various Gram-negative species belonging to the class Bacteroidia. Our results reveal functional surfaces related to pathogenic properties of polymerized FimA. These insights may facilitate development of antibacterial drugs.