Subtilase
Protein family
From Wikipedia, the free encyclopedia
Subtilases are a family of subtilisin-like serine proteases. They appear to have independently and convergently evolved an Asp/Ser/His catalytic triad, like in the trypsin serine proteases. The structure of proteins in this family shows that they have an alpha/beta fold containing a 7-stranded parallel beta sheet.
| Subtilase3 family | |||||||
|---|---|---|---|---|---|---|---|
Structure of the complex formed between subtilisin Carlsberg and eglin c, an elastase inhibitor from the leech Hirudo medicinalis.[1] | |||||||
| Identifiers | |||||||
| Symbol | Peptidase_S8 | ||||||
| Pfam | PF00082 | ||||||
| InterPro | IPR000209 | ||||||
| PROSITE | PDOC00125 | ||||||
| MEROPS | S8 | ||||||
| SCOP2 | 1cse / SCOPe / SUPFAM | ||||||
| CDD | cd00306 | ||||||
| Membranome | 546 | ||||||
| |||||||
The subtilisin family is the second largest serine protease family characterised to date. Over 200 subtilases are presently known, more than 170 of which with their complete amino acid sequence.[2] Subtilase is widespread, being found in eubacteria, archaebacteria, eukaryotes and viruses.[3] The vast majority of the family are endopeptidases, although there is an exopeptidase, tripeptidyl peptidase.[3][4] Structures have been determined for several members of the subtilisin family showing that subtilisins exploit the same catalytic triad as the chymotrypsins although the residues occur in a different order (His/Asp/Ser in chymotrypsin and Asp/His/Ser in subtilisin); otherwise the structures show similarity to no other proteins.[3][4] Some subtilisins are mosaic proteins, whereas others contain N- and C-terminal extensions that show no sequence similarity to any other known protein.[3] Based on sequence homology, a subdivision into six families has been proposed.[2]
The proprotein-processing endopeptidases kexin, furin and related enzymes form a distinct subfamily known as the kexin subfamily (S8B). These preferentially cleave C-terminally to paired basic amino acids. Members of this subfamily can be identified by subtly different motifs around the active site.[3][4] Members of the kexin family, along with endopeptidases R, T and K from the yeast Tritirachium and cuticle-degrading peptidase from Metarhizium, require thiol activation. This can be attributed to the presence of Cys-173 near to the active histidine.[4] Only 1 viral member of the subtilisin family is known, a 56-kDa protease from herpes virus 1, which infects the channel catfish.[3]
Sedolisins (serine-carboxyl peptidases) are proteolytic enzymes whose fold resembles that of subtilisin; however, they are considerably larger, with the mature catalytic domains containing approximately 375 amino acids. The defining features of these enzymes are a unique catalytic triad, Ser/Glu/Asp, as well as the presence of an aspartic acid residue in the oxyanion hole. High-resolution crystal structures have now been solved for sedolisin from Pseudomonas sp. 101, as well as for kumamolisin from a thermophilic bacterium, Bacillus novo sp. MN-32. Mutations in the human gene leads to a fatal neurodegenerative disease.[5]
