| Type: | Family | Name: | Peptidase M3B, oligoendopeptidase-related clade 2 |
| 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 consists of probable oligoendopeptidases belonging to MEROPS peptidase family M3, subfamily M3B (clan MA(E)). The family is related to lactococcal PepF and group B streptococcal PepB () but in a distinct clade with considerable sequence differences not only to but also to . Likely substrates are small peptides and not whole proteins, as with PepF, but members are not characterised and the activity profile may differ. Several bacteria have both a member of this family and a member of the PepF family. | Short Name: | Pept_M3B_clade2 |
