Homologous Superfamily

Bacteriophage, G3P, N2-domain superfamily (IPR013834)

Short name: Phage_G3P_N2_sf

Overlapping entries



The G3P protein (also known as attachment protein or coat protein A) of filamentous phage such as M13, phage fd and phage f1, is an essential coat protein for the infection of Escherichia coli. The G3P protein consists of three domains: two N-terminal domains (N1 and N2) with a similar beta-barrel fold, and a C-terminal domain [PMID: 9461080]. The N-terminal domains protrude from the phage surface, while the C-terminal domain acts as an anchor embedded in the phage coat, together forming a horseshoe-like structure [PMID: 12767837]. The G3P protein exists as 3-5 copies at the tip of the phage particle.

Infection by filamentous phage occurs in two steps, both of which are mediated by the G3P protein: phage attachment to the F-pilus of the host cell as the primary receptor, followed by attachment to the C-terminal domain of the periplasmic protein TolA as a co-receptor.

This superfamily represents the second N-terminal domain, N2, of the filamentous phage coat protein G3P.

GO terms

Biological Process

GO:0009405 pathogenesis

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0019028 viral capsid

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.