M18 family aminopeptidase catalyzes the removal of amino acids from the N termini of peptides, similar to aspartyl aminopeptidase, which displays specificity towards an acidic amino acid at the N-terminus, with a preference for aspartate
M18 peptidase aminopeptidase family; Peptidase M18 aminopeptidase family is widely distributed ...
6-424
0e+00
M18 peptidase aminopeptidase family; Peptidase M18 aminopeptidase family is widely distributed in bacteria and eukaryotes, but only the yeast aminopeptidase I and mammalian aspartyl aminopeptidase have been characterized to date. Yeast aminopeptidase I is active only in its dodecameric form with broad substrate specificity, acting on N-terminal leucine and most other amino acids. In contrast, the mammalian aspartyl aminopeptidase is highly selective for hydrolysis of N-terminal Asp or Glu residues from peptides. These enzymes have two catalytic zinc ions at the active site.
Pssm-ID: 349892 Cd Length: 430 Bit Score: 692.35 E-value: 0e+00
M18 peptidase aminopeptidase family; Peptidase M18 aminopeptidase family is widely distributed ...
6-424
0e+00
M18 peptidase aminopeptidase family; Peptidase M18 aminopeptidase family is widely distributed in bacteria and eukaryotes, but only the yeast aminopeptidase I and mammalian aspartyl aminopeptidase have been characterized to date. Yeast aminopeptidase I is active only in its dodecameric form with broad substrate specificity, acting on N-terminal leucine and most other amino acids. In contrast, the mammalian aspartyl aminopeptidase is highly selective for hydrolysis of N-terminal Asp or Glu residues from peptides. These enzymes have two catalytic zinc ions at the active site.
Pssm-ID: 349892 Cd Length: 430 Bit Score: 692.35 E-value: 0e+00
M18 peptidase aspartyl aminopeptidase; Peptidase M18 family, aspartyl aminopeptidase (DAP; EC 3.4.11.21) subfamily, is widely distributed in bacteria and eukaryotes. DAP cleaves only unblocked N-terminal acidic amino-acid residues. It is a cytosolic enzyme and is highly conserved; for example, the human enzyme has 51% identity to an aspartyl aminopeptidase-like protein in Arabidopsis thaliana. The mammalian DAP is highly selective for hydrolysis of N-terminal aspartate or glutamate residues from peptides. Unlike glutamyl aminopeptidase (M42), DAP does not cleave simple aminoaryl-arylamide substrates. Although there is lack of understanding of the function of this enzyme, it is thought to act in concert with other aminopeptidases to facilitate protein turnover because of their restricted specificities for the N-terminal aspartic and glutamic acid, which cannot be cleaved by any other aminopeptidases. The mammalian aspartyl aminopeptidase is possibly contributing to the catabolism of peptides, including those produced by the proteasome. It may also trim the N-terminus of peptides that are intended for the MHC class I system. In humans, DAP has been implicated in the specific function of converting angiotensin II to the vasoactive angiotensin III within the brain. Saccharomyces cerevisiae aminopeptidase I (Ape1) is involved in protein degradation in vacuoles (the yeast lysosomes) where it is transported by the unique cytoplasm-to-vacuole targeting (Cvt) pathway under vegetative growth conditions and by the autophagy pathway during starvation. Its N-terminal propeptide region, which mediates higher-order complex formation, serves as a scaffolding cargo critical for the assembly of the Cvt vesicle for vacuolar delivery. Pseudomonas aeruginosa aminopeptidase (PaAP) shows that its activity is dependent on Co2+ rather than Zn2+, and is thus a cocatalytic cobalt peptidase rather than a zinc-dependent peptidase.
Pssm-ID: 349908 Cd Length: 439 Bit Score: 656.92 E-value: 0e+00
M18 peptidase aminopeptidase I; Peptidase M18 family, aminopeptidase I (vacuolar aminopeptidase I; polypeptidase; Leucine aminopeptidase IV; LAPIV; aminopeptidase III; aminopeptidase yscI; EC 3.4.11.22) subfamily. Aminopeptidase I is widely distributed in bacteria and eukaryotes, but only the yeast enzyme has been characterized to date. It is a vacuolar enzyme, synthesized as a cytosolic proform, and proteolytically matured upon arrival in the vacuole. The pro-aminopeptidase I (proAPI) does not enter the vacuole via the secretory pathway. In non-starved cells, it uses the cytoplasm to vacuole targeting (cvt) pathway and in cells starved for nitrogen, it is targeted to the vacuole via autophagy. Yeast aminopeptidase I is active only in its dodecameric form with broad substrate specificity, acting on all aminoacyl and peptidyl derivatives that contain a free alpha-amino group; this is in contrast to the highly selective M18 mammalian aspartyl aminopeptidase. N-terminal leucine and most other hydrophobic amino acid residues are the best substrates while glycine and charged amino acid residues in P1 position are cleaved much more slowly. This enzyme is strongly and specifically activated by zinc (Zn2+) and chloride (Cl-) ions.
Pssm-ID: 349909 Cd Length: 446 Bit Score: 156.77 E-value: 3.96e-43
M42 Peptidase, endoglucanases; Peptidase M42 family, Frv (Frv Operon Protein; Endo-1 4-Beta-Glucanase; Cellulase Protein; Endoglucanase; Endo-1 4-Beta-Glucanase Homolog; Glucanase; EC. 3.2.1.4) subfamily. Frv is a co-catalytic metallopeptidase, found in archaea and bacteria, including Pyrococcus horikoshii tetrahedral shaped phTET1 (DAPPh1; FrvX; PhDAP aminopeptidase; PhTET aminopeptidase; deblocking aminopeptidase), phTET2 (DAPPh2) and phTET3 (DAPPh3), Haloarcula marismortui TET (HmTET) as well as Bacillus subtilis YsdC. All of these exhibit aminopeptidase and deblocking activities. The HmTET is a broad substrate aminopeptidase capable of degrading large peptides. PhTET2, which shares 24% identity with HmTET, is a cobalt-activated peptidase and possibly a deblocking aminopeptidase, assembled as a 12-subunit tetrahedral dodecamer, while PhTET1 can be alternatively assembled as a tetrahedral dodecamer or as an octahedral tetracosameric structure. The active site in such a self-compartmentalized complex is located on the inside such that substrate sizes are limited, indicating function as possible peptide scavengers. PhTET2 cleaves polypeptides by a nonprocessive mechanism, preferring N-terminal hydrophobic or uncharged polar amino acids. Streptococcus pneumoniae PepA (SpPepA) also forms dodecamer with tetrahedral architecture, and exhibits selective substrate specificity to acidic amino acids with the preference to glutamic acid, with the substrate binding S1 pocket containing an Arg allows electrostatic interactions with the N-terminal acidic residue in the substrate. The YsdC gene is conserved in a number of thermophiles, archaea and pathogenic bacterial species; the closest structural homolog is Thermotoga maritima FrwX (34% identity), which is annotated as either a cellulase or an endoglucanase, and is possibly involved in polysaccharide biosynthesis or degradation.
Pssm-ID: 349906 [Multi-domain] Cd Length: 337 Bit Score: 54.49 E-value: 4.27e-08
M42 glutamyl aminopeptidase; These peptidases are found in Archaea and Bacteria. The example ...
225-417
6.01e-07
M42 glutamyl aminopeptidase; These peptidases are found in Archaea and Bacteria. The example in Lactococcus lactis, PepA, aids growth on milk. Pyrococcus horikoshii contain a thermostable de-blocking aminopeptidase member of this family used commercially for N-terminal protein sequencing.
Pssm-ID: 428431 [Multi-domain] Cd Length: 292 Bit Score: 50.65 E-value: 6.01e-07
Zinc peptidases M18, M20, M28, and M42; Zinc peptidases play vital roles in metabolic and ...
216-405
7.10e-04
Zinc peptidases M18, M20, M28, and M42; Zinc peptidases play vital roles in metabolic and signaling pathways throughout all kingdoms of life. This hierarchy contains zinc peptidases that correspond to the MH clan in the MEROPS database, which contains 4 families (M18, M20, M28, M42). The peptidase M20 family includes carboxypeptidases such as the glutamate carboxypeptidase from Pseudomonas, the thermostable carboxypeptidase Ss1 of broad specificity from archaea and yeast Gly-X carboxypeptidase. The dipeptidases include bacterial dipeptidase, peptidase V (PepV), a non-specific eukaryotic dipeptidase, and two Xaa-His dipeptidases (carnosinases). There is also the bacterial aminopeptidase, peptidase T (PepT) that acts only on tripeptide substrates and has therefore been termed a tripeptidase. Peptidase family M28 contains aminopeptidases and carboxypeptidases, and has co-catalytic zinc ions. However, several enzymes in this family utilize other first row transition metal ions such as cobalt and manganese. Each zinc ion is tetrahedrally co-ordinated, with three amino acid ligands plus activated water; one aspartate residue binds both metal ions. The aminopeptidases in this family are also called bacterial leucyl aminopeptidases, but are able to release a variety of N-terminal amino acids. IAP aminopeptidase and aminopeptidase Y preferentially release basic amino acids while glutamate carboxypeptidase II preferentially releases C-terminal glutamates. Glutamate carboxypeptidase II and plasma glutamate carboxypeptidase hydrolyze dipeptides. Peptidase families M18 and M42 contain metallo-aminopeptidases. M18 is widely distributed in bacteria and eukaryotes. However, only yeast aminopeptidase I and mammalian aspartyl aminopeptidase have been characterized in detail. Some M42 (also known as glutamyl aminopeptidase) enzymes exhibit aminopeptidase specificity while others also have acylaminoacyl-peptidase activity (i.e. hydrolysis of acylated N-terminal residues).
Pssm-ID: 349870 [Multi-domain] Cd Length: 200 Bit Score: 40.49 E-value: 7.10e-04
Database: CDSEARCH/cdd Low complexity filter: no Composition Based Adjustment: yes E-value threshold: 0.01
References:
Wang J et al. (2023), "The conserved domain database in 2023", Nucleic Acids Res.51(D)384-8.
Lu S et al. (2020), "The conserved domain database in 2020", Nucleic Acids Res.48(D)265-8.
Marchler-Bauer A et al. (2017), "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures.", Nucleic Acids Res.45(D)200-3.
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