title: Structural basis for recognition of the type VI spike protein VgrG3 by a cognate immunity protein.
abstract: The bacterial type VI secretion system (T6SS) is used by donor cells to inject toxic effectors into receptor cells. The donor cells produce the corresponding immunity proteins to protect themselves against the effector proteins, thereby preventing their self-intoxication. Recently, the C-terminal domain of VgrG3 was identified as a T6SS effector. Information on the molecular mechanism of VgrG3 and its immunity protein TsaB has been lacking. Here, we determined the crystal structures of native TsaB and the VgrG3C-TsaB complex. VgrG3C adopts a canonical phage-T4-lysozyme-like fold. TsaB interacts with VgrG3C through molecular mimicry, and inserts into the VgrG3C pocket.
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China; School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Jiulong
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, and Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, No. 5 Yiheyuan Road, Beijing 100871, People's Republic of China.
authors.forename: Heng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
authors.forename: Zengqiang
authors.initials: Z
authors.lastname: Gao
authors.affiliation: Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People's Republic of China.
authors.forename: Haidai
authors.initials: H
authors.lastname: Hu
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China; State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, People's Republic of China. Electronic address: dongcheng@ihep.ac.cn.
authors.forename: Cheng
authors.initials: C
authors.lastname: Dong
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China. Electronic address: dongyh@ihep.ac.cn.
authors.forename: Yu-Hui
authors.initials: YH
authors.lastname: Dong
mesh_terms: D000992:Antitoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D058947:Bacterial Secretion Systems; D001665:Binding Sites / Q000235:genetics; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D011485:Protein Binding; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D012996:Solutions / Q000737:chemistry; D020349:Surface Plasmon Resonance; D014961:X-Ray Diffraction
chemical_list: D000992:Antitoxins; D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D046912:Multiprotein Complexes; D012996:Solutions; C581031:TsaB protein, Vibrio cholerae; C581030:VgrG-3 protein, Vibrio cholerae
keywords: Glycosyl hydrolase; T4-lysozyme-like fold; The type VI secretion system; VgrG3–TsaB complex