Family M42
Summary for family M42
| Name | Peptidase family M42 (glutamyl aminopeptidase family) |
|---|
| Family type peptidase | M42.001 - glutamyl aminopeptidase (bacterium) (Lactococcus lactis), MEROPS Accession MER0002040 (peptidase unit: 1-355) |
| Content of family | Peptidase family M42 contains metalloaminopeptidases some of which also have acylaminoacylpeptidase activity. |
| History |
Identifier created: Handbook of Proteolytic Enzyme, Academic Press, London (1998)
Relevant recent reviews are those of Motoshima & Kaminogawa, 2004, Niven, 2004 and Tsunasawa, 2004. |
| Catalytic type | Metallo |
| Active site residues | H65 D67 D181 E213 E214 D,E236 H319 |
| Active site | These peptidases are co-catalytic metallopeptidases, typically binding two atoms of zinc or cobalt. See above for the locations of the catalytic residues and metal ligands. |
| Activities and specificities | Some of the enzymes exhibit typical aminopeptidase specificity, whereas others are also able to hydrolyse acylated N-terminal residues, the so-called 'N-terminal deblocking activity'. Characteristics commonly reported are exceptional thermal stability and a requirement for cobalt ions for maximal activity (Roncari et al., 1972; Ando et al., 1999; Onoe et al., 2002). |
| Molecular structure | Indications of the three-dimensional molecular structure were obtained for M42.005 from Haloarcula marismortui by electron microscopy (Franzetti et al., 2002), and crystal structures have been solved for an unclassified member of the family from Bacillus subtilis (M42.UPW; PDB/1VHE) and for the aminopeptidase from Pyrococcus horikoshii (M42.003; Russo & Baumann 2004). The aminopeptidases exist as complexes of twelve identical subunits in which all the active sites are located in the interior of the molecule, and access of substrates is restricted by 10-Angstrom pores. |
| Clan | MH |
| Basis of clan assignment | For members of this family and family M28 predicted metal ligands occur in the same order in the sequence: H, D, E, D/E, H; and active site residues in the motifs HXD and EE |
| Peptidases and Homologues |
MEROPS ID |
Structure |
| glutamyl aminopeptidase (bacterium) | M42.001 | Yes |
| aminopeptidase I beta chain (Bacillus-type) | M42.002 | - |
| PhTET1 aminopeptidase | M42.003 | Yes |
| PhTET2 aminopeptidase | M42.004 | Yes |
| TET aminopeptidase | M42.005 | - |
| FrvX putative peptidase | M42.006 | Yes |
| TM1048-type putative peptidase | M42.007 | Yes |
| YpdE-type putative peptidase | M42.008 | Yes |
| PhTET3 aminopeptidase | M42.009 | Yes |
| CelM peptidase | M42.010 | - |
| aminopeptidase I alpha chain (Bacillus-type) | M42.011 | Yes |
| SgcX protein (Escherichia coli) | M42.A01 | - |
| yhfE g.p. (Bacillus subtilis) | M42.A02 | - |
| Family M42 non-peptidase homologues | non-peptidase homologue | - |
| Family M42 unassigned peptidases | unassigned | Yes |
