9x3p

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

spinqualitylabelsall models 9x3p, resolution 3.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9x3p is a 34 chain structure with sequence from Escherichia phage T4. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.5Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TSP_BPT4 Structural component of the bacteriophage tail which consists of a contractile sheath, a tube and a baseplate. The central cylindrical segment of the tail consists of a rigid tube, composed of multiple copies of gp19, surrounded by the outer contractile sheath assembled from gp18 subunits. A total of 138 copies of gp18 arranged into 23 hexameric rings constitutes the sheath. During infection, contraction of the sheath drives the central tube through the host outer membrane, creating a channel for DNA ejection from the capsid into the host cell. Publication Abstract from PubMed 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. Cryo-EM Structures of Phage T4 Infection Intermediate.,Shao Q, Dong J, Wang A, Hu H, Yue J, Li H, Li Y, Zhang Q, Liu J, Sun L, Fokine A, Rao VB, Tao P, Fang Q J Mol Biol. 2026 Jul 4;438(19):169938. doi: 10.1016/j.jmb.2026.169938. PMID:42401366 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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