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0  structures 42  species 0  interactions 102  sequences 11  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

In the MEROPS database peptidases and peptidase homologues are grouped into clans and families. Clans are groups of families for which there is evidence of common ancestry based on a common structural fold:

  • Each clan is identified with two letters, the first representing the catalytic type of the families included in the clan (with the letter 'P' being used for a clan containing families of more than one of the catalytic types serine, threonine and cysteine). Some families cannot yet be assigned to clans, and when a formal assignment is required, such a family is described as belonging to clan A-, C-, M-, N-, S-, T- or U-, according to the catalytic type. Some clans are divided into subclans because there is evidence of a very ancient divergence within the clan, for example MA(E), the gluzincins, and MA(M), the metzincins.
  • Peptidase families are grouped by their catalytic type, the first character representing the catalytic type: A, aspartic; C, cysteine; G, glutamic acid; M, metallo; N, asparagine; S, serine; T, threonine; and U, unknown. The serine, threonine and cysteine peptidases utilise the amino acid as a nucleophile and form an acyl intermediate - these peptidases can also readily act as transferases. In the case of aspartic, glutamic and metallopeptidases, the nucleophile is an activated water molecule. In the case of the asparagine endopeptidases, the nucleophile is asparagine and all are self-processing endopeptidases.

In many instances the structural protein fold that characterises the clan or family may have lost its catalytic activity, yet retain its function in protein recognition and binding.

Aspartic endopeptidases EC of vertebrate, fungal and retroviral origin have been characterised [PUBMED:1455179]. More recently, aspartic endopeptidases associated with the processing of bacterial type 4 prepilin [PUBMED:10625704] and archaean preflagellin have been described [PUBMED:16983194, PUBMED:14622420].

Structurally, aspartic endopeptidases are bilobal enzymes, each lobe contributing a catalytic Asp residue, with an extended active site cleft localised between the two lobes of the molecule. One lobe has probably evolved from the other through a gene duplication event in the distant past. In modern-day enzymes, although the three-dimensional structures are very similar, the amino acid sequences are more divergent, except for the catalytic site motif, which is very conserved. The presence and position of disulphide bridges are other conserved features of aspartic peptidases. All or most aspartate peptidases are endopeptidases. These enzymes have been assigned into clans (proteins which are evolutionary related), and further sub-divided into families, largely on the basis of their tertiary structure.

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

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

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 using the family HMM. We also generate alignments using four representative proteomes (RP) sets, 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
(6)
Full
(102)
Representative proteomes NCBI
(125)
Meta
(0)
RP15
(1)
RP35
(17)
RP55
(19)
RP75
(23)
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1Cannot generate PP/Heatmap alignments for seeds; no PP data available

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

Format an alignment

  Seed
(6)
Full
(102)
Representative proteomes NCBI
(125)
Meta
(0)
RP15
(1)
RP35
(17)
RP55
(19)
RP75
(23)
Alignment:
Format:
Order:
Sequence:
Gaps:
Download/view:

Download options

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
(6)
Full
(102)
Representative proteomes NCBI
(125)
Meta
(0)
RP15
(1)
RP35
(17)
RP55
(19)
RP75
(23)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download    
Gzipped 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.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

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: 6
Number in full: 102
Average length of the domain: 173.90 aa
Average identity of full alignment: 29 %
Average coverage of the sequence by the domain: 22.75 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.3 21.3
Trusted cut-off 21.4 21.5
Noise cut-off 20.7 21.1
Model length: 201
Family (HMM) version: 10
Download: download the raw HMM for this family

Species distribution

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