Attachment protein G3P, N-terminal (IPR008021)

Short name: Attachment_G3P_N

Overlapping homologous superfamilies

Domain relationships



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 involves two distinct cellular receptors, the F' pilus and the periplasmic protein TolA, which are bound sequentially [PMID: 10329170]. The N2 domain binds the F' pilus, causing a conformational change which allows the N1 domain to bind the C-terminal domain of TolA as a co-receptor.

This entry represents the two N-terminal domains, N1 and N2, of G3P.

Contributing signatures

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