9X3Q

Phage T4 inner baseplate in post-tail-contraction state (genome-full particle)

Summary for 9X3Q

• Entry DOI: 10.2210/pdb9x3q/pdb
• EMDB information: 66506
• Descriptor: Baseplate wedge protein gp6, Baseplate wedge protein gp7, Baseplate wedge protein gp25, ... (5 entities in total)
• Functional Keywords: bacteriophage, myovirus, phage t4, tail contraction, phage neck complex, viral protein
• Biological source: Escherichia phage T4; More
• Total number of polymer chains: 7
• Total formula weight: 343383.01

Authors

Shao, Q.,Dong, J.,Wang, A.,Hu, H.,Yue, J.,Li, H.,Li, Y.,Zhang, Q.,Liu, J.,Sun, L.,Fokine, A.,Rao, V.B.,Tao, P.,Fang, Q. (deposition date: 2025-10-09, release date: 2026-07-22)

Primary citation

Shao, Q.,Dong, J.,Wang, A.,Hu, H.,Yue, J.,Li, H.,Li, Y.,Zhang, Q.,Liu, J.,Sun, L.,Fokine, A.,Rao, V.B.,Tao, P.,Fang, Q.
Cryo-EM structures of phage T4 infection intermediate.
J.Mol.Biol., :169938-169938, 2026

PubMed Abstract: Myophage is endowed with a sophisticated contractile tail and infection machinery. However, the mechanisms of host recognition, signal transduction, and genome delivery remain poorly understood. Here, we capture a pre-genome-release intermediate of myophage T4 and determine its structure by cryo-electron microscopy. Comparative analysis of this tail-contracted, pre-genome-release intermediate structure with the mature T4 virion and the tail-contracted, post-genome-release structure reveals structural transitions in the tail, tape-measure protein (TMP), baseplate, and long tail fibers that drive genome delivery. Our findings further suggest that tail sheath contraction is coupled to a coordinated repositioning of the viral DNA-TMP complex, potentially facilitating genome translocation via charge-mediated interactions. It appears that the expelled TMP may further reorganize into a putative transmembrane complex that supports genome delivery into the host cytosol.

PubMed: 42401366
DOI: 10.1016/j.jmb.2026.169938

Experimental method

ELECTRON MICROSCOPY (3.7 Å)