Structure and assembly of type VI secretion system cargo delivery vehicle
Wenbo He,
Ke Wu,
Zhenlin Ouyang,
Yixin Bai,
Wen Luo,
Di Wu,
Hao An,
Yucheng Guo,
Min Jiao,
Qian Qin,
Jiaxin Zhang,
Yi Wu,
Junjun She,
Peter M. Hwang,
Fang Zheng,
Li Zhu,
Yurong Wen
Affiliations
Wenbo He
Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi’an Jiaotong University, Xi’an 710061, China
Ke Wu
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
Zhenlin Ouyang
Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi’an Jiaotong University, Xi’an 710061, China
Yixin Bai
Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi’an Jiaotong University, Xi’an 710061, China
Wen Luo
Department of Oncology, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
Di Wu
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
Hao An
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
Yucheng Guo
The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi’an Jiaotong University, Xi’an 710061, China
Min Jiao
Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi’an Jiaotong University, Xi’an 710061, China
Qian Qin
Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi’an Jiaotong University, Xi’an 710061, China
Jiaxin Zhang
The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi’an Jiaotong University, Xi’an 710061, China
Yi Wu
The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi’an Jiaotong University, Xi’an 710061, China
Junjun She
Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi’an Jiaotong University, Xi’an 710061, China
Peter M. Hwang
Department of Biochemistry, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2R3, Canada
Fang Zheng
The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi’an Jiaotong University, Xi’an 710061, China
Li Zhu
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China; Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou 730000, China; Corresponding author
Yurong Wen
Center for Microbiome Research of Med-X Institute, Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, The First Affiliated Hospital, Xi’an Jiaotong University, Xi’an 710061, China; The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi’an Jiaotong University, Xi’an 710061, China; Corresponding author
Summary: Type VI secretion system is widely used in Gram-negative bacteria for injecting toxic effectors into neighboring prokaryotic or eukaryotic cells. Various effectors can be loaded onto the T6SS delivery tube via its core components: Hcp, VgrG, or PAAR. Here, we report 2.8-Å resolution cryo-EM structure of intact T6SS Hcp5-VgrG-PAAR cargo delivery system and crystal structure of unbound Hcp5 from B. fragilis NCTC 9343. Loading of Hcp5 hexameric ring onto VgrG causes expansion of its inner cavity and external surface, explaining how structural changes could be propagated to regulate co-polymerization and surrounding contractile sheath. High-affinity binding between Hcp and VgrG causes entropically unfavorable structuring of long loops. Furthermore, interactions between VgrG trimer and Hcp hexamer are asymmetric, with three of the six Hcp monomers exhibiting a major loop flip. Our study provides insights into the assembly, loading, and firing of T6SS nanomachine that contributes to bacterial inter-species competition and host interactions.
