Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France.
Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France.
Sci Rep. 2020 Apr 30;10(1):7384. doi: 10.1038/s41598-020-64115-z.
Porphyromonas gingivalis, the major human pathogen associated to periodontal diseases, utilizes the Bacteroidetes-specific type IX secretion system (T9SS) to export virulence factors. PorE is a periplasmic multi-domain lipoprotein associated to the outer membrane that was recently identified as essential for T9SS function. Little is known on T9SS at the structural level, and in particular its interaction with peptidoglycan. This prompted us to carry out structural studies on PorE full length as well as on its four isolated domains. Here we report the crystal structure of the C-terminal OmpA_C-like putative peptidoglycan-binding domain at 1.55 Å resolution. An electron density volume was identified in the protein cleft, making it possible to build a naturally-occurring peptidoglycan fragment. This result suggests that PorE interacts with peptidoglycan and that PorE could anchor T9SS to the cell wall.
牙龈卟啉单胞菌是与牙周病相关的主要人类病原体，利用拟杆菌特异性的九型分泌系统（T9SS）来输出毒力因子。PorE 是一种与外膜相关的周质多结构域脂蛋白，最近被确定为 T9SS 功能所必需的。在结构水平上，对 T9SS 的了解甚少，特别是它与肽聚糖的相互作用。这促使我们对全长 PorE 及其四个分离结构域进行结构研究。在这里，我们报道了 1.55Å分辨率的 C 端 OmpA_C 样假定肽聚糖结合结构域的晶体结构。在蛋白质裂缝中鉴定到一个电子密度体积，从而有可能构建一个天然存在的肽聚糖片段。这一结果表明，PorE 与肽聚糖相互作用，并且 PorE 可以将 T9SS 锚定在细胞壁上。
