v5.1.0.3
Cicer data from the Legume Information System
Type | Family |
Description | Over 70 metallopeptidase families have been identified to date. In these enzymes a divalent cation which is usually zinc, but may be cobalt, manganese or copper, activates the water molecule. The metal ion is held in place by amino acid ligands, usually three in number. In some families of co-catalytic metallopeptidases, two metal ions are observed in crystal structures ligated by five amino acids, with one amino acid ligating both metal ions. The known metal ligands are His, Glu, Asp or Lys. At least one other residue is required for catalysis, which may play an electrophillic role. Many metalloproteases 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 includes Xaa-Arg dipeptidases ( also known as beta-Ala-Lys dipeptidases), metallopeptidases that belong to the M20A peptidase family, subfamily D (MEROPS M20.021). These proteins catalyse the peptide bond hydrolysis in dipeptides having basic amino acids lysine, ornithine or arginine at C-terminal. They may function in a metabolite repair mechanism by eliminating alternate dipeptide by-products formed during carnosine synthesis [ ]. |
Short Name | Xaa-Arg_dipeptidase |