Family M54


Summary Holotypes Alignment Tree Genomes Structure Literature H-seq M-seq

Summary for family M54

Family type peptidaseM54.001 - archaelysin (Methanocaldococcus jannaschii), MEROPS Accession MER0011900 (peptidase unit: 1-179)
Content of familyPeptidase family M54 contains aminopeptidases, sometimes termed archaelysins or archaemetzincins.
History Identifier created: MEROPS 7.4 (17 Mar 2006)
The family was first identified in the genome sequencing of archaea. The proteins were provisionally identified as peptidases from the conservation of motifs found in the Met-zincins (subclan MA(M)). None of the archaean peptidases has been characterized, but two human homologues have been reported to degrade synthetic substrates and peptides (Diaz-Perales et al., 2005). This would be the first family of exopeptidases known in subclan MA(M).
Catalytic typeMetallo
Active site residuesH128 E129 H132 H,N138 
Active siteMetal binding ligands are assumed to be the histidines in the HEXXHXXGXXH motif and the conserved glutamate is assumed to be a catalytic residue. In human aminopeptidase AMZ1 (M54.003) the third zinc ligand is replaced by Asn.
Activities and specificitiesThe two human peptidases have been reported to be aminopeptidases. Eukaryote archelysin (M54.002) has a preference for arginine in P1; the AMZ1 protein (M54.950) cleaves alanyl bonds. The peptidases differ in their pH optima, with AMZ1 having the more alkaline preference (pH 8.0) (Diaz-Perales et al., 2005).
InhibitorsBoth human peptidases are inhibited by amastatin, 1,10-phenanthroline and batimastat (Diaz-Perales et al., 2005).
Molecular structureNo structures have been solved for any member of the family. Members of the family contain the extended zinc-binding motif (HEXXHXXGXXH) and Met-turn found in members of subclan MA(M), and the family is assigned accordingly. The assignment has been confirmed by comparison of Hidden Markov models for the families in the subclan.
Basis of clan assignmentActive site residues for members of this family and thermolysin, the type example for clan MA, occur in the motif HEXXH
Distribution of family Bacteria details  
Archaea details  
Protozoa details  
Fungi details  
Plants -  
Animals details  
Viruses -  
Biological functions
Statistics for family M54Sequences:779
Identifiers with PDB entries:1
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Phylogenetic tree (Newick format)
Peptidases and Homologues MEROPS ID Structure
aminopeptidase AMZ2M54.002-
aminopeptidase AMZ1M54.003-
family M54 non-peptidase homologuesnon-peptidase homologue-
family M54 unassigned peptidasesunassigned-