Pathways & interactions
PatG/PatA-like domain (IPR034056)
Short name: Pep_S8_PatG/PatA-like
Overlapping homologous superfamilies
- Peptidase S8/S53 domain superfamily (IPR036852)
- Peptidase S8/S53 domain (IPR000209)
- PatG/PatA-like domain (IPR034056)
This entry includes the subtilisin-like peptidase domain of the PatG peptidase (also known as the thiazoline oxidase/subtilisin-like protease; MEROPS identifier S08.146) which is produced by the symbiotic bacteria Prochloron spp. that inhabit didemnid family ascidians. The cyclic peptides of the patellamide class found in didemnid extracts are now known to be synthesized by the Prochloron spp. The prepatellamide is heterocyclized to form thiazole and oxazoline rings and the peptide is cleaved to form the two cyclic patellamides A and C [PMID: 17086177]. Two peptidases are required for the release of the active peptide from its precursor. PatA peptidase (MEROPS identifier S08.156) cleaves off the N-terminal propeptide, and the PatG peptidase releases the C-terminal propeptide and cyclizes the patellamide [PMID: 23177196]. Unusually, cleavage by PatG occurs at a cystinyl bond. The tertiary structure of the PatG peptidase domain shows a unique element not found in other subtilisin homologues that may be responsible for the N-C macrocyclization of the patellamide [PMID: 23177196].
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].
- cd07476 (Peptidases_S8_thiazoline_oxida)