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Title | Structure and assembly of type VI secretion system cargo delivery vehicle. |
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Journal, issue, pages | Cell Rep, Vol. 42, Issue 7, Page 112781, Year 2023 |
Publish date | Jul 25, 2023 |
Authors | 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 / |
PubMed Abstract | 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 ...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. |
External links | Cell Rep / PubMed:37421630 |
Methods | EM (single particle) / X-ray diffraction |
Resolution | 1.98 - 2.8 Å |
Structure data | EMDB-34087: The cargo delivery vehicle Hcp-VgrG-PAAR of the Type VI secretion system PDB-7yw0: |
Chemicals | ChemComp-HOH: |
Source |
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Keywords | STRUCTURAL PROTEIN / Hcp5 / Bacteroides fragilis / T6SS / TRANSPORT PROTEIN / Type VI Secretion System / VgrG / PAAR |