Peptidase M38, beta-aspartyl dipeptidase (IPR010229)

Short name: Pept_M38_dipep

Overlapping homologous superfamilies

Family relationships


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 [PMID: 7674922]. 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 [PMID: 7674922].

This group of proteins include metallopeptidases belonging to the MEROPS peptidase family M38 (clan MJ, beta-aspartyl dipeptidase family). This entry includes the beta-aspartyl dipeptidase from Escherichia coli, (EC:, IadA; MEROPS identifier M38.001), which degrades isoaspartyl dipeptides and may unblock degradation of proteins that cannot be repaired. This entry also describes closely related proteins from other species (e.g. Clostridium perfringens, Thermoanaerobacter tengcongensis) that may have an equivalent in function. This family shows homology to dihydroorotases. The L-isoaspartyl derivative of Asp arises non-enzymatically over time as a form of protein damage. In this isomerisation, the connectivity of the polypeptide changes to pass through the beta-carboxyl of the side chain. Much but not all of this damage can be repaired by protein-L-isoaspartate (D-aspartate) O-methyltransferase.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0008798 beta-aspartyl-peptidase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.