Peptidase M1, alanyl aminopeptidase (IPR012779)

Short name: Peptidase_M1_pepN

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].

The M1 family of zinc metallopeptidases contains a number of distinct, well-separated clades of proteins with aminopeptidase activity. Several are designated aminopeptidase N, EC:, after the Escherichia coli enzyme, suggesting a similar activity profile (see P04825 for a description of catalytic activity).

This group of zinc metallopeptidases belong to MEROPS peptidase family M1 (aminopeptidase N, clan MA); the majority are identified as alanyl aminopeptidases (proteobacteria) that are closely related to E. coli PepN and presumed to have a similar (not identical) function. Nearly all are found in proteobacteria, but members are found also in cyanobacteria, plants, and apicomplexan parasites [PMID: 15109723, PMID: 14663077]. This family differs greatly in sequence from the family of aminopeptidases typified by Streptomyces lividans PepN (IPR012778) and from the membrane bound aminopeptidase N family in animals.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0008270 zinc ion binding

Cellular Component

No terms assigned in this category.

Contributing signatures

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