Peptidase U9, T4 prohead protease (IPR005082)

Short name: Peptidase_U9_T4_prohead

Overlapping homologous superfamilies


Family relationships



This group of peptidases belongs to MEROPS peptidase family U9 (phage prohead processing peptidase family, clan U-), which play a role in the head assembly of Bacteriophage T4.

The pathway of bacteriophage T4 head assembly begins with the formation of a prohead bound to the bacterial cell membrane which is later converted to the mature, DNA-containing head. During maturation, all but one of the prohead proteins are proteolytically processed by a phage-coded protease which is formed by autocatalytic cleavage of the product of gene 21 (gp21). Protease gp21 has been tentatively located in the centre of the prohead core [PMID: 3552886].

The peptidases families associated with clan U- have an unknown catalytic mechanism as the protein fold of the active site domain and the active site residues have not been reported.

Contributing signatures

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