9JG6

The tail-complex structure of phage P22

This is a non-PDB format compatible entry.

Summary for 9JG6

• Entry DOI: 10.2210/pdb9jg6/pdb
• EMDB information: 61457
• Descriptor: Portal protein, Endorhamnosidase, Phage stabilisation protein, ... (4 entities in total)
• Functional Keywords: complex, viral protein
• Biological source: Salmonella enterica subsp. enterica serovar Typhimurium; More
• Total number of polymer chains: 48
• Total formula weight: 2820187.54

Authors

Liu, H.R.,Xiao, H. (deposition date: 2024-09-06, release date: 2025-02-26, Last modification date: 2025-04-30)

Primary citation

Xiao, H.,Chen, W.,Pang, H.,Zheng, J.,Wang, L.,Feng, H.,Song, J.,Cheng, L.,Liu, H.
Structure of the scaffolding protein and portal within the bacteriophage P22 procapsid provides insights into the self-assembly process.
Plos Biol., 23:e3003104-e3003104, 2025

PubMed Abstract: In the assembly pathway of tailed double-stranded DNA (dsDNA) bacteriophages and herpesviruses, a procapsid with a dodecameric portal for DNA delivery at a unique vertex is initially formed. Appropriate procapsid assembly requires the transient presence of multiple copies of a scaffolding protein (SP), which is absent in the mature virion. However, how the SP contributes to dodecameric portal formation, facilitates portal and coat protein incorporation, and is subsequently released remains unclear because of a lack of structural information. Here, we present the structure of the SP-portal complex within the procapsid of bacteriophage P22 at 3-9 Å resolutions. The AlphaFold2-predicted SP model fits well with the density map of the complex. The SP forms trimers and tetramers that interact to yield a dome-like complex on the portal. Two SP domains mediate multimerization. Each trimer interacts with two neighboring portal subunits. The SP has a loop-hook-like structure that aids in coat protein recruitment during viral assembly. The loops of those SP subunits on the portal are positioned in clefts between adjacent portal subunits. Conformational changes in the portal during phage maturation may trigger the disassembly and release of the SP complex. Our findings provide insights into SP-assisted procapsid assembly in bacteriophage P22 and suggest that this strategy is also implemented by other dsDNA viruses, including herpesviruses.

PubMed: 40245015
DOI: 10.1371/journal.pbio.3003104

Experimental method

ELECTRON MICROSCOPY (3.21 Å)