Department of Medical Biochemistry and Biophysics, Umeå University, 90187, Umeå, Sweden.
Department of Medical Biochemistry and Biophysics, Umeå University, 90187, Umeå, Sweden; Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden.
Structure. 2022 Jun 2;30(6):876-885.e5. doi: 10.1016/j.str.2022.03.013. Epub 2022 Apr 15.
Multidrug-resistant bacteria pose serious problems in hospital-acquired infections (HAIs). Most antibiotic resistance genes are acquired via conjugative gene transfer, mediated by type 4 secretion systems (T4SS). Although most multidrug-resistant bacteria responsible for HAIs are of Gram-positive origin, with enterococci being major contributors, mostly Gram-negative T4SSs have been characterized. Here, we describe the structure and organization of PrgL, a core protein of the T4SS channel, encoded by the pCF10 plasmid from Enterococcus faecalis. The structure of PrgL displays similarity to VirB8 proteins of Gram-negative T4SSs. In vitro experiments show that the soluble domain alone is enough to drive both dimerization and dodecamerization, with a dimerization interface that differs from all other known VirB8-like proteins. In vivo experiments verify the importance of PrgL dimerization. Our findings provide insight into the molecular building blocks of Gram-positive T4SS, highlighting similarities but also unique features in PrgL compared to other VirB8-like proteins.
多重耐药菌在医院获得性感染（HAIs）中构成严重问题。大多数抗生素耐药基因是通过转导基因转移获得的，介导因子为 4 型分泌系统（T4SS）。尽管大多数导致 HAI 的耐药菌来自革兰阳性菌，肠球菌是主要贡献者，但已鉴定出大多数革兰阴性 T4SS。在这里，我们描述了来自粪肠球菌的 pCF10 质粒编码的 T4SS 通道核心蛋白 PrgL 的结构和组织。PgL 的结构与革兰氏阴性 T4SS 的 VirB8 蛋白相似。体外实验表明，可溶性结构域本身足以驱动二聚化和十二聚化，其二聚化界面与所有其他已知的 VirB8 样蛋白不同。体内实验验证了 PrgL 二聚化的重要性。我们的发现为革兰氏阳性 T4SS 的分子构建块提供了深入了解，突出了 PrgL 与其他 VirB8 样蛋白相比的相似之处和独特特征。
