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0  structures 6  species 0  interactions 6  sequences 2  architectures

Family: Peptidase_A3 (PF02160)

Summary: Cauliflower mosaic virus peptidase (A3)

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Cauliflower mosaic virus peptidase (A3) Provide feedback

No Pfam abstract.

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR000588

Aspartic peptidases, also known as aspartyl proteases (EC), are widely distributed proteolytic enzymes [PUBMED:6795036, PUBMED:2194475, PUBMED:1851433] known to exist in vertebrates, fungi, plants, protozoa, bacteria, archaea, retroviruses and some plant viruses. All known aspartic peptidases are endopeptidases. A water molecule, activated by two aspartic acid residues, acts as the nucleophile in catalysis. Aspartic peptidases can be grouped into five clans, each of which shows a unique structural fold [PUBMED:8439290].

  • Peptidases in clan AA are either bilobed (family A1 or the pepsin family) or are a homodimer (all other families in the clan, including retropepsin from HIV-1/AIDS) [PUBMED:2682266]. Each lobe consists of a single domain with a closed beta-barrel and each lobe contributes one Asp to form the active site. Most peptidases in the clan are inhibited by the naturally occurring small-molecule inhibitor pepstatin [PUBMED:4912600].
  • Clan AC contains the single family A8: the signal peptidase 2 family. Members of the family are found in all bacteria. Signal peptidase 2 processes the premurein precursor, removing the signal peptide. The peptidase has four transmembrane domains and the active site is on the periplasmic side of the cell membrane. Cleavage occurs on the amino side of a cysteine where the thiol group has been substituted by a diacylglyceryl group. Site-directed mutagenesis has identified two essential aspartic acid residues which occur in the motifs GNXXDRX and FNXAD (where X is a hydrophobic residue) [PUBMED:10497172]. No tertiary structures have been solved for any member of the family, but because of the intramembrane location, the structure is assumed not to be pepsin-like.
  • Clan AD contains two families of transmembrane endopeptidases: A22 and A24. These are also known as "GXGD peptidases" because of a common GXGD motif which includes one of the pair of catalytic aspartic acid residues. Structures are known for members of both families and show a unique, common fold with up to nine transmembrane regions [PUBMED:21765428]. The active site aspartic acids are located within a large cavity in the membrane amnd into which water can gain access [PUBMED:23254940].
  • Clan AE contains two families, A25 and A31. Tertiary structures have been solved for members of both families and show a common fold consisting of an alpha-beta-alpha sandwich, in which the beta sheet is five stranded [PUBMED:10331925, PUBMED:10864493].
  • Clan AF contains the single family A26. Members of the clan are membrane-proteins with a unique fold. Homologues are known only from bacteria. The structure of omptin (also known as OmpT) shows a cylindrical barrel containing ten beta strands inserted in the membrane with the active site residues on the outer surface [PUBMED:11566868].
  • There are two families of aspartic peptidases for which neither structure nor active site residues are known and these are not assigned to clans. Family A5 includes thermopsin, an endopeptidase found only in thermophilic archaea. Family A36 contains sporulation factor SpoIIGA, which is known to process and activate sigma factor E, one of the transcription factors that controls sporulation in bacteria [PUBMED:21751400].

This group of sequences contain an aspartic peptidase signature that belongs to MEROPS peptidase family A3, subfamily A3A (cauliflower mosaic virus-type endopeptidase, clan AA). Cauliflower mosaic virus belongs to the Retro-transcribing viruses, which have a double-stranded DNA genome. The genome includes an open reading frame (ORF V) that shows similarities to the pol gene of retroviruses. This ORF codes for a polyprotein that includes a reverse transcriptase, which, on the basis of a DTG triplet near the N terminus, was suggested to include an aspartic protease. The presence of an aspartic protease has been confirmed by mutational studies, implicating Asp-45 in catalysis. The protease releases itself from the polyprotein and is involved in reactions required to process the ORF IV polyprotein, which includes the viral coat protein [PUBMED:7674916]. The viral aspartic peptidase signature has also been found associated with a polyprotein encoded by integrated pararetrovirus-like sequences in the genome of Nicotiana tabacum (Common tobacco) [PUBMED:10557305].

Gene Ontology

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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 Peptidase_AA (CL0129), which has the following description:

This clan contains aspartic peptidases, including the pepsins and retropepsins. These enzymes contains a catalytic dyad composed of two aspartates. In the retropepsins one is provided by each copy of a homodimeric protein, whereas in the pepsin-like peptidases these aspartates come from a single protein composed of two duplicated domains.

The clan contains the following 14 members:

Asp Asp_protease Asp_protease_2 DUF1758 gag-asp_proteas Peptidase_A2B Peptidase_A2E Peptidase_A3 RVP RVP_2 Spuma_A9PTase TAXi_C TAXi_N Zn_protease

Alignments

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
(2)
Full
(6)
Representative proteomes UniProt
(160)
NCBI
(220)
Meta
(1)
RP15
(4)
RP35
(4)
RP55
(5)
RP75
(5)
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PP/heatmap 1 View               

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

  Seed
(2)
Full
(6)
Representative proteomes UniProt
(160)
NCBI
(220)
Meta
(1)
RP15
(4)
RP35
(4)
RP55
(5)
RP75
(5)
Alignment:
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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
(2)
Full
(6)
Representative proteomes UniProt
(160)
NCBI
(220)
Meta
(1)
RP15
(4)
RP35
(4)
RP55
(5)
RP75
(5)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download   Download  

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 View help on the curation process

Seed source: IPR000588
Previous IDs: none
Type: Family
Author: Mian N, Bateman A
Number in seed: 2
Number in full: 6
Average length of the domain: 196.00 aa
Average identity of full alignment: 18 %
Average coverage of the sequence by the domain: 29.76 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 17690987 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.3 21.3
Trusted cut-off 21.3 21.4
Noise cut-off 21.2 21.1
Model length: 205
Family (HMM) version: 13
Download: download the raw HMM for this family

Species distribution

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Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence

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