Family A32
Summary for family A32
| Family type peptidase | A32.001 - PerP peptidase (Caulobacter sp.) (Caulobacter crescentus), MEROPS Accession MER0151383 (peptidase unit: 1-172) |
| Content of family | |
| History |
Identifier created: MEROPS 9.5 (1 July 2011)
The bacterium Caulobacter crescentus alternates between sessile and motile cell cycles. Motility is associated with the 'swarmer' phenomenon, where bacterial cells act in unison rather like a multicellular organism, whereas the sessile form adheres to a surface. In the motile form each cell has pili and a flagellum, whereas in the sessile form these organelles are replaced by a stalk. Assymetric cell division results in the production of a daughter sessile cell and a daughter swarmer cell. The PodJ protein is a transmembrane factor that recruits essential proteins to the correct cell pole. In the swarmer phase, full-length PodJ (known as PodJL) recruits proteins required for pilus formation. As the cell divides, PodJ is cleaved to a truncated form known as PodJS. PodJS protein remains attached to the membrane, where it recruits components required for stalk formation as the cell moves into the sessile stage. PerP is a periplasmic protein in Caulobacter rescentus that converts PodJL to PodJS (Chen et al., 2006). |
| Catalytic type | Aspartic |
| Active site residues | D80 |
| Active site | An Asp which occurs in a conserved Asp-Thr-Gly motif is assumed to be the active site residue, and by analogy to the HIV1 retropepsin (A02.001) the peptidase is presumed to be only active as a homodimer (Chen et al., 2006). |
| Molecular structure | From the sequence, PerP is a multidomain protein, with either an N-terminal signal peptide or transmembrane region, and a C-terminal, periplasmic, aspartic peptidase domain. No tertiary structure for any member of the family has been solved, but family A32 is included in clan AA because of the Asp-Gly-Thr motif and a weak sequence relationship to the peptidase from retrotransposon Osvaldo (A02.054). |
| Clan | AA |
| Basis of clan assignment | Protein fold of the peptidase unit for members of this family resembles that of retropepsin. |
