| Type: | Family | Name: | Peptidase M12A, nematode astacin 9/10/11 |
| Description: | Metalloproteases are the most diverse of the four main types of protease, with more than 50 families identified to date. In these enzymes, a divalent cation, usually zinc, activates the water molecule. The metal ion is held in place by amino acid ligands, usually three in number. The known metal ligands are His, Glu, Asp or Lys and at least one other residue is required for catalysis, which may play an electrophillic role. Of the known metalloproteases, around half contain an HEXXH motif, which has been shown in crystallographic studies to form part of the metal-binding site []. The HEXXH motif is relatively common, but can be more stringently defined for metalloproteases as 'abXHEbbHbc', where 'a' is most often valine or threonine and forms part of the S1' subsite in thermolysin and neprilysin, 'b' is an uncharged residue, and 'c' a hydrophobic residue. Proline is never found in this site, possibly because it would break the helical structure adopted by this motif in metalloproteases [].This family of metallopeptidases are found in Caenorhabditis elegansand belong to MEROPS peptidase family M12A (astacin, clan MA). They hydrolys peptide bonds in substrates containing five or more amino acids, preferentially with Ala in P1', and Pro in P2'. In the nematode C. elegans, 40 genes code for astacin-like proteins (nematode astacins, NAS). The astacins are metalloproteases present in bacteria, invertebrates and vertebrates and serve a variety of physiological functions like digestion, hatching, peptide processing, morphogenesis and pattern formation [].This group represents a zinc metalloproteinase, nas-9/10/11 types. | Short Name: | Peptidase_M12A_astacin-9/10/11 |
