9Q7A

dsDNA in the central channel of the bacteriophage P74-26 neck

This is a non-PDB format compatible entry.

Summary for 9Q7A

• Entry DOI: 10.2210/pdb9q7a/pdb
• EMDB information: 72288
• Descriptor: DNA (66-MER) (2 entities in total)
• Functional Keywords: bacteriophage, thermophilic, neck, portal, virus, virus-dna complex, virus/dna
• Biological source: Oshimavirus P7426; More
• Total number of polymer chains: 2
• Total formula weight: 40695.00

Authors

Sedivy, E.L.,Agnello, E.,Song, K.,Xu, C.,Kelch, B.A. (deposition date: 2025-08-22, release date: 2026-01-28)

Primary citation

Sedivy, E.L.,Agnello, E.,Hobaugh, J.E.,Ahsan, R.,Song, K.,Xu, C.,Kelch, B.A.
The structure of a thermostable phage's portal vertex and neck complex illuminates the headful maturation mechanism.
J.Mol.Biol., :169641-169641, 2026

PubMed Abstract: Viruses assemble from component parts inside their host cells, but the mechanisms coordinating this complex process are not completely understood. In tailed bacteriophages, the genome is packaged into its capsid shell through the portal complex. The portal complex then closes to retain DNA and connects to the tail, which is required for host recognition and infection. The trigger to stop pumping DNA and assemble the mature virus has been a longstanding conundrum in the field. We determined the structure of the portal, the proteins that connect it to the tail, and portal vertex in the hyperthermophilic phage Oshimavirus using cryo-Electron Microscopy (cryo-EM). We find highly intertwined loop structures, like in a wicker basket, potentially stabilizing the portal vertex against high temperatures. Moreover, we observe that the portal protrudes from the capsid in mature virions. We propose that portal is repositioned by packaged DNA, forming a pressure-sensitive switch that terminates genome packaging and triggers tail attachment in headful phages.

PubMed: 41544933
DOI: 10.1016/j.jmb.2026.169641

Experimental method

ELECTRON MICROSCOPY (4.54 Å)