- PDB-6h3l: Structure of VgrG1 in the Type VI secretion "pre-firing" VgrG1-Ts... -
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基本情報
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データベース: PDB / ID: 6h3l
タイトル
Structure of VgrG1 in the Type VI secretion "pre-firing" VgrG1-Tse6-EagT6-EF-Tu-Tsi6 complex
要素
VgrG1
キーワード
TOXIN (毒素) / Bacterial Type VI effector complex / T6SS chaperone-effector complex / Tse6-loaded VgrG1 complex / NAD(P)+ Glycohydrolase
機能・相同性
機能・相同性情報
type VI protein secretion system complex / protein secretion by the type VI secretion system / extracellular region 類似検索 - 分子機能
Type VI secretion system, RhsGE-associated Vgr family subset / Phage tail baseplate hub (GPD) / Type VI secretion system, RhsGE-associated Vgr protein / Gp5/Type VI secretion system Vgr protein, OB-fold domain / Type VI secretion system/phage-baseplate injector OB domain / Vgr protein, OB-fold domain superfamily 類似検索 - ドメイン・相同性
Type VI secretion system spike protein VgrG1a 類似検索 - 構成要素
ジャーナル: Nat Microbiol / 年: 2018 タイトル: Mechanism of loading and translocation of type VI secretion system effector Tse6. 著者: Dennis Quentin / Shehryar Ahmad / Premy Shanthamoorthy / Joseph D Mougous / John C Whitney / Stefan Raunser / 要旨: The type VI secretion system (T6SS) primarily functions to mediate antagonistic interactions between contacting bacterial cells, but also mediates interactions with eukaryotic hosts. This molecular ...The type VI secretion system (T6SS) primarily functions to mediate antagonistic interactions between contacting bacterial cells, but also mediates interactions with eukaryotic hosts. This molecular machine secretes antibacterial effector proteins by undergoing cycles of extension and contraction; however, how effectors are loaded into the T6SS and subsequently delivered to target bacteria remains poorly understood. Here, using electron cryomicroscopy, we analysed the structures of the Pseudomonas aeruginosa effector Tse6 loaded onto the T6SS spike protein VgrG1 in solution and embedded in lipid nanodiscs. In the absence of membranes, Tse6 stability requires the chaperone EagT6, two dimers of which interact with the hydrophobic transmembrane domains of Tse6. EagT6 is not directly involved in Tse6 delivery but is crucial for its loading onto VgrG1. VgrG1-loaded Tse6 spontaneously enters membranes and its toxin domain translocates across a lipid bilayer, indicating that effector delivery by the T6SS does not require puncturing of the target cell inner membrane by VgrG1. Eag chaperone family members from diverse Proteobacteria are often encoded adjacent to putative toxins with predicted transmembrane domains and we therefore anticipate that our findings will be generalizable to numerous T6SS-exported membrane-associated effectors.