InterPro : IPR004634

Name  Peptidase S49, protease IV Short Name  Pept_S49_pIV
Type  Family Description  Proteolytic enzymes that exploit serine in their catalytic activity are ubiquitous, being found in viruses, bacteria and eukaryotes []. They include a wide range of peptidase activity, including exopeptidase, endopeptidase, oligopeptidase and omega-peptidase activity. Many families of serine protease have been identified, these being grouped into clans on the basis of structural similarity and other functional evidence []. Structures are known for members of the clans and the structures indicate that some appear to be totally unrelated, suggesting different evolutionary origins for the serine peptidases [].Not withstanding their different evolutionary origins, there are similarities in the reaction mechanisms of several peptidases. Chymotrypsin, subtilisin and carboxypeptidase C have a catalytic triad of serine, aspartate and histidine in common: serine acts as a nucleophile, aspartate as an electrophile, and histidine as a base []. The geometric orientations of the catalytic residues are similar between families, despite different protein folds []. The linear arrangements of the catalytic residues commonly reflect clan relationships. For example the catalytic triad in the chymotrypsin clan (PA) is ordered HDS, but is ordered DHS in the subtilisin clan (SB) and SDH in the carboxypeptidase clan (SC) [, ].This group of serine peptidases belong to MEROPS peptidase family S49 (protease IV family, clan S-). The predicted active site serine for members of this family occurs in a transmembrane domain.Signal peptides of secretory proteins seem to serve at least two important biological functions. First, they are required forprotein targeting to and translocation across membranes, such as the eubacterial plasma membrane and the endoplasmicreticular membrane of eukaryotes. Second, in addition to their role as determinants for proteintargeting and translocation, certain signal peptides have a signalling function.During or shortly after pre-protein translocation, the signal peptide is removed by signal peptidases. The integral membrane protein, SppA (protease IV), of Escherichia coliwas shown experimentally to degrade signal peptides. The member of this family from Bacillus subtilishas only been shown to be required for efficient processing ofpre-proteins under conditions of hyper-secretion []. These enzymes have a molecular mass around 67 kDa and a duplication such that the N-terminal half shares extensive homology with the C-terminal half and was shown in E. coli to form homotetramers. E. coli SohB, which is most closely homologous to the C-terminal duplication of SppA, is predicted to perform a similar function of small peptide degradation, but in the periplasm.Many prokaryotes have a single SppA/SohB homologue that may perform the function of either or both.

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

1 Contains

Id Name Short Name Type
IPR002142 Peptidase S49 Peptidase_S49 Domain

0 Found In

0 Parent Features

3 Publications

First Author Title Year Journal Volume Pages
Rawlings ND Evolutionary families of peptidases. 1993 Biochem J 290 ( Pt 1) 205-18
Rawlings ND Families of serine peptidases. 1994 Methods Enzymol 244 19-61
Bolhuis A Signal peptide peptidase- and ClpP-like proteins of Bacillus subtilis required for efficient translocation and processing of secretory proteins. 1999 J Biol Chem 274 24585-92

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)