Pathways & interactions
CspA-like domain (IPR034045)
Short name: Pep_S8_CspA-like
Overlapping homologous superfamilies
- Peptidase S8/S53 domain (IPR000209)
- CspA-like domain (IPR034045)
This entry includes the peptidase domain of the subtilisin homologues CspA (MEROPS identifier S08.159), CspB (MEROPS identifier S08.108) and CspC (MEROPS identifier S08.158) from Clostridium species. These peptidases are important for the initiation of spore germination by activation of the hydrolase hydrolase SleC, which degrades the protective cortex layer of the spore, allowing it to germinate. In Clostridium perfringens, all three subtilisin homologues are active peptidases, but in C. difficile, CspA and CspC are described as "pseudopeptidases" [PMID: 26231446], because active site residues have been mutated. In C. difficile, dormant spores are activated by the binding of bile salts, especially taurocholate, to CspC. SleC is activated by a CspA/CspB fusion protein [PMID: 26231446].
This domain is part of a family of domains found in serine peptidases belonging to the MEROPS peptidase families S8 (subfamilies S8A (subtilisin) and S8B (kexin)) and S53 (sedolisin), both of which are members of clan SB [PMID: 9070434, PMID: 7845208, PMID: 8439290, PMID: 12673349].
Peptidases S8 (or subtilases serine endo- and exo-peptidase clan) have an Asp/His/Ser catalytic triad similar to that found in trypsin-like proteases, but do not share their three-dimensional structure and are not homologous to trypsin. The stability of subtilases may be enhanced by calcium, some members have been shown to bind up to 4 ions via binding sites with different affinity. Some members of this clan contain disulfide bonds. These enzymes can be intra- and extracellular, some function at extreme temperatures and pH values [PMID: 1798697, PMID: 8420571, PMID: 8439290, PMID: 9070434].
- cd07478 (Peptidases_S8_CspA-like)