Tail accessory factor GP4 (IPR020362)

Short name: Tail_accessory_Gp4

Overlapping homologous superfamilies

Family relationships



The tail complex in bacteriophage P22, and related phages, mediates host cell attachement and DNA injection. Tail assembly is a complex event that is essential for the retention and stabilisation of the newly packaged DNA within the capsid. This process involves the the sequential addition of three tail accessory factors (GP4, GP10, GP26) and the adhesion tailspike protein (GP9) to the capsid-bound portal protein [PMID: 21310457].

GP4 is the first factor to attach after DNA packaging. Twelve monomeric subunits of GP4 bind to the exposed surface of the portal ring, beginning the tail assembly process. GP4 does not physically block the DNA entry/exit channel, but appears to act as a structural adaptor for the other tail accessory factors GP10 and GP26 [PMID: 16970964].

Gp4 has been shown to have peptidoglycan hydrolase activity [PMID: 14763988].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
  • PD097046 (Packaged_DNA_stabilis_prot_Gp4)