VirB7 和 VirB9 相互作用对于 IV 型分泌系统的组装和抗菌活性是必需的。
VirB7 and VirB9 Interactions Are Required for the Assembly and Antibacterial Activity of a Type IV Secretion System.
机构信息
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo 05508-000, Brazil.
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo 05508-000, Brazil.
出版信息
Structure. 2016 Oct 4;24(10):1707-1718. doi: 10.1016/j.str.2016.07.015. Epub 2016 Sep 1.
The type IV secretion system (T4SS) from the phytopathogen Xanthomonas citri (Xac) is a bactericidal nanomachine. The T4SS core complex is a ring composed of multiple copies of VirB7-VirB9-VirB10 subunits. Xac-VirB7 contains a disordered N-terminal tail (VirB7) that recognizes VirB9, and a C-terminal domain (VirB7) involved in VirB7 self-association. Here, we show that VirB7 forms a short β strand upon binding to VirB9 and stabilizes it. A tight interaction between them is essential for T4SS assembly and antibacterial activity. Abolishing VirB7 self-association or deletion of the VirB7 C-terminal domain impairs this antibacterial activity without disturbing T4SS assembly. These findings reveal protein interactions within the core complex that are critical for the stability and activity of a T4SS.
植物病原菌黄单胞菌（Xanthomonas citri，Xac）的 IV 型分泌系统（T4SS）是一种杀菌纳米机器。T4SS 核心复合物是由多个 VirB7-VirB9-VirB10 亚基组成的环。Xac-VirB7 包含一个无规卷曲的 N 端尾巴（VirB7），该尾巴识别 VirB9，以及一个参与 VirB7 自我组装的 C 端结构域（VirB7）。在这里，我们表明 VirB7 在与 VirB9 结合后形成一个短的β链，并稳定了它。它们之间的紧密相互作用对于 T4SS 组装和抗菌活性是必不可少的。破坏 VirB7 自我组装或删除 VirB7 C 端结构域会损害这种抗菌活性，而不会干扰 T4SS 组装。这些发现揭示了核心复合物内对于 T4SS 的稳定性和活性至关重要的蛋白质相互作用。
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