7YW0

Bacteroides fragilis Hcp5

Summary for 7YW0

• Entry DOI: 10.2210/pdb7yw0/pdb
• Descriptor: Bacterodales T6SS protein TssD (Hcp) (2 entities in total)
• Functional Keywords: hcp5, bacteroides fragilis, t6ss, structural protein
• Biological source: Bacteroides fragilis
• Total number of polymer chains: 2
• Total formula weight: 29010.56

Authors

Wen, Y.,He, W.,Bai, Y. (deposition date: 2022-08-20, release date: 2023-08-30)

Primary citation

He, W.,Wu, K.,Ouyang, Z.,Bai, Y.,Luo, W.,Wu, D.,An, H.,Guo, Y.,Jiao, M.,Qin, Q.,Zhang, J.,Wu, Y.,She, J.,Hwang, P.M.,Zheng, F.,Zhu, L.,Wen, Y.
Structure and assembly of type VI secretion system cargo delivery vehicle.
Cell Rep, 42:112781-112781, 2023

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 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.

PubMed: 37421630
DOI: 10.1016/j.celrep.2023.112781

Experimental method

X-RAY DIFFRACTION (1.98 Å)