Family A32


Summary Holotypes Alignment Tree Genomes Structure Literature

Summary for family A32

Family type peptidaseA32.001 - 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 typeAspartic
Active site residuesD80 
Active siteFrom the solved tertiary structure, an Asp which occurs in a conserved Asp-Thr-Gly motif is the active site residue, and the peptidase is active as a homodimer (Li et al., 2015).
Molecular structureFrom 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. The tertiary structure of the RC1339 protein from Rickettsia conorii has been solved, and shows a retropepsin-like fold (Li et al., 2015). Family A32 is included in clan AA because of the similar fold.
Basis of clan assignmentProtein fold of the peptidase unit for members of this family resembles that of retropepsin.
Distribution of family Bacteria details  
Archaea details  
Protozoa -  
Fungi details  
Plants details  
Animals details  
Viruses -  
Biological functionsImportant for processing the polar factor PodJ, which recruits proteins to the correct cell pole during cell division.
Statistics for family A32Sequences:630
Identifiers with PDB entries:1
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Phylogenetic tree (Newick format)
Peptidases and Homologues MEROPS ID Structure
PerP peptidase (Caulobacter sp.)A32.001-
RC1339 g.p. (Rickettsia conorii)A32.002Yes
non-peptidase homologue-
family A32 unassigned peptidasesunassigned-