Summary

Cauliflower mosaic virus peptidase (A3)

No Pfam abstract.

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-, 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; 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 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 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.

Clan

This family is a member of clan Peptidase_AA (CL0129), which contains the following 10 members:

Asp Asp_protease DUF1758 HutD Peptidase_A2B Peptidase_A2E Peptidase_A3 RVP RVP_2 Spuma_A9PTase

Gene Ontology

Molecular function	aspartic-type endopeptidase activity (GO:0004190)
Biological process	proteolysis (GO:0006508)

Internal database links

SCOOP:

RVP_2 TUDOR XPA_C

External database links

MEROPS:	A3
PANDIT:	PF02160
PRINTS:	PR00731
SYSTERS:	Peptidase_A3

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Alignments

There are various ways to view or download the sequence alignments that we store. You can use a sequence viewer to look at either the seed or full alignment for the family, or you can look at a plain text version of the sequence in a variety of different formats. More...

View options

Alignment:	Seed (6) Full (65) NCBI (86) Metagenomics
Viewer:

Formatting options

Alignment:	Seed (6) Full (65)
Format:
Order:	Tree Alphabetical
Sequence:	Inserts lower case All upper case
Gaps:
Download/view:	Download View

Download options

Very large alignments can often cause problems for the formatting tool above. If you find that downloading or viewing a large alignment is problematic, you can also download a gzip-compressed, Stockholm-format file containing the seed or full alignment for this family.

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

The main seed and full alignments are generated using sequences from the UniProt sequence database. However, we also generate alignments using sequences from the NCBI sequence database and the "metaseq" metagenomics dataset.

You can view alignments from these two additional datasets using the form above, or you can download alignments of NCBI or metagenomics sequences, as gzip-compressed files.

Pfam alignments:	Seed (6) Full (65) NCBI (86) Metagenomics
Full length sequences	Full-sequences (65)

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 HMMER2.

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. 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 or full alignments.

Note: You can also download the data files for the seed, full, NCBI or metagenomics trees.

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:

IPR000588

Previous IDs:

none

Type:

Family

Author:

Mian N, Bateman A

Number in seed:

6

Number in full:

65

Average length of the domain:

178.60 aa

Average identity of full alignment:

33 %

Average coverage of the sequence by the domain:

24.50 %

HMM information

HMM build commands:

build method: hmmbuild -o /dev/null HMM SEED

search method: hmmsearch -Z 9421015 -E 1000 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	21.3	21.3
Trusted cut-off	21.4	21.4
Noise cut-off	21.2	21.2

Model length:

201

Family (HMM) version:

8

Download:

download the raw HMM for this family

Species distribution

Tree controls

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The tree shows the occurrence of this domain across different species. More...

Species trees

We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.

Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.

If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.

Interactive tree

For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.

We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.

Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.

We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.

You can use the tree controls to manipulate how the interactive tree is displayed:

show/hide the summary boxes
highlight species that are represented in the seed alignment
expand/collapse the tree or expand it to a given depth
select a sub-tree or a set of species within the tree and view them graphically or as an alignment
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Family: Peptidase_A3 (PF02160)

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