Summary: Peptidase C26
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Peptidase C26 Provide feedback
These peptidases have gamma-glutamyl hydrolase activity; that is they catalyse the cleavage of the gamma-glutamyl bond in poly-gamma-glutamyl substrates. They are structurally related to PF00117 but contain extensions in four loops and at the C terminus [1].
Literature references
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Li H, Ryan TJ, Chave KJ, Van Roey P; , J Biol Chem 2002;277:24522-24529.: Three-dimensional structure of human gamma -glutamyl hydrolase. A class I glatamine amidotransferase adapted for a complex substate. PUBMED:11953431 EPMC:11953431
Internal database links
SCOOP: | CbiA DJ-1_PfpI GATase GATase_3 GATase_5 HTS SNO |
Similarity to PfamA using HHSearch: | GATase GATase_3 |
External database links
MEROPS: | C26 |
This tab holds annotation information from the InterPro database.
InterPro entry IPR011697
These peptidases have gamma-glutamyl hydrolase activity; that is they catalyse the cleavage of the gamma-glutamyl bond in poly-gamma-glutamyl substrates. They are structurally related to , but contain extensions in four loops and at the C terminus [PUBMED:11953431]. They belong to MEROPS peptidase family C26 (gamma-glutamyl hydrolase family), clan PC. The majority of the sequences are classified as unassigned peptidases.
A cysteine peptidase is a proteolytic enzyme that hydrolyses a peptide bond using the thiol group of a cysteine residue as a nucleophile. Hydrolysis involves usually a catalytic triad consisting of the thiol group of the cysteine, the imidazolium ring of a histidine, and a third residue, usually asparagine or aspartic acid, to orientate and activate the imidazolium ring. In only one family of cysteine peptidases, is the role of the general base assigned to a residue other than a histidine: in peptidases from family C89 (acid ceramidase) an arginine is the general base. Cysteine peptidases can be grouped into fourteen different clans, with members of each clan possessing a tertiary fold unique to the clan. Four clans of cysteine peptidases share structural similarities with serine and threonine peptidases and asparagine lyases. From sequence similarities, cysteine peptidases can be clustered into over 80 different families [PUBMED:11517925]. Clans CF, CM, CN, CO, CP and PD contain only one family.
Cysteine peptidases are often active at acidic pH and are therefore confined to acidic environments, such as the animal lysosome or plant vacuole. Cysteine peptidases can be endopeptidases, aminopeptidases, carboxypeptidases, dipeptidyl-peptidases or omega-peptidases. They are inhibited by thiol chelators such as iodoacetate, iodoacetic acid, N-ethylmaleimide or p-chloromercuribenzoate.
Clan CA includes proteins with a papain-like fold. There is a catalytic triad which occurs in the order: Cys/His/Asn (or Asp). A fourth residue, usually Gln, is important for stabilising the acyl intermediate that forms during catalysis, and this precedes the active site Cys. The fold consists of two subdomains with the active site between them. One subdomain consists of a bundle of helices, with the catalytic Cys at the end of one of them, and the other subdomain is a beta-barrel with the active site His and Asn (or Asp). There are over thirty families in the clan, and tertiary structures have been solved for members of most of these. Peptidases in clan CA are usually sensitive to the small molecule inhibitor E64, which is ineffective against peptidases from other clans of cysteine peptidases [PUBMED:7044372].
Clan CD includes proteins with a caspase-like fold. Proteins in the clan have an alpha/beta/alpha sandwich structure. There is a catalytic dyad which occurs in the order His/Cys. The active site His occurs in a His-Gly motif and the active site Cys occurs in an Ala-Cys motif; both motifs are preceded by a block of hydrophobic residues [PUBMED:9891971]. Specificity is predominantly directed towards residues that occupy the S1 binding pocket, so that caspases cleave aspartyl bonds, legumains cleave asparaginyl bonds, and gingipains cleave lysyl or arginyl bonds.
Clan CE includes proteins with an adenain-like fold. The fold consists of two subdomains with the active site between them. One domain is a bundle of helices, and the other a beta barrell. The subdomains are in the opposite order to those found in peptidases from clan CA, and this is reflected in the order of active site residues: His/Asn/Gln/Cys. This has prompted speculation that proteins in clans CA and CE are related, and that members of one clan are derived from a circular permutation of the structure of the other.
Clan CL includes proteins with a sortase B-like fold. Peptidases in the clan hydrolyse and transfer bacterial cell wall peptides. The fold shows a closed beta barrel decorated with helices with the active site at one end of the barrel [PUBMED:14725770]. The active site consists of a His/Cys catalytic dyad.
Cysteine peptidases with a chymotrypsin-like fold are included in clan PA, which also includes serine peptidases. Cysteine peptidases that are N-terminal nucleophile hydrolases are included in clan PB. Cysteine peptidases with a tertiary structure similar to that of the serine-type aspartyl dipeptidase are included in clan PC. Cysteine peptidases with an intein-like fold are included in clan PD, which also includes asparagine lyases.
Gene Ontology
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
Molecular function | hydrolase activity (GO:0016787) |
Domain organisation
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
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Pfam Clan
This family is a member of clan Glutaminase_I (CL0014), which has the following description:
Most members of this clan are glutaminase enzymes. This superfamily is shown to be related in [1]. The clan also contains the DJ-1/PfpI family that includes the peptidase PfpI that has a catalytic Cys-His-Glu triad that differs from the class I GAT Cys-His-Glu triad.
The clan contains the following 18 members:
ABC_transp_aux BPL_N Catalase_C DJ-1_PfpI DUF4159 GATase GATase1_like GATase_3 GATase_5 Glyco_hydro_42M HTS LBP_M Peptidase_C26 Peptidase_S51 Peptidase_S66 SNO ThiJ_like ThuAAlignments
We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the UniProtKB sequence database, the NCBI sequence database, and our metagenomics sequence database. More...
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We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.
Seed (34) |
Full (5666) |
Representative proteomes | UniProt (24204) |
NCBI (217918) |
Meta (9652) |
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RP15 (742) |
RP35 (2569) |
RP55 (5443) |
RP75 (9427) |
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PP/heatmap | 1 |
1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key:
available,
not generated,
— not available.
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We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.
Seed (34) |
Full (5666) |
Representative proteomes | UniProt (24204) |
NCBI (217918) |
Meta (9652) |
||||
---|---|---|---|---|---|---|---|---|---|
RP15 (742) |
RP35 (2569) |
RP55 (5443) |
RP75 (9427) |
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Raw Stockholm | |||||||||
Gzipped |
You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.
HMM logo
HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...
Trees
This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.
Note: You can also download the data file for the tree.
Curation and family details
This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.
Curation
Seed source: | MEROPS |
Previous IDs: | none |
Type: | Domain |
Sequence Ontology: | SO:0000417 |
Author: |
Studholme DJ |
Number in seed: | 34 |
Number in full: | 5666 |
Average length of the domain: | 205.30 aa |
Average identity of full alignment: | 28 % |
Average coverage of the sequence by the domain: | 73.81 % |
HMM information
HMM build commands: |
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 47079205 -E 1000 --cpu 4 HMM pfamseq
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Model details: |
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Model length: | 216 | ||||||||||||
Family (HMM) version: | 14 | ||||||||||||
Download: | download the raw HMM for this family |
Species distribution
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Interactions
There is 1 interaction for this family. More...
Peptidase_C26Structures
For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Peptidase_C26 domain has been found. There are 38 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.
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