Summary

Proteasome subunit

The proteasome is a multisubunit structure that degrades proteins. Protein degradation is an essential component of regulation because proteins can become misfolded, damaged, or unnecessary. Proteasomes and their homologues vary greatly in complexity: from HslV (heat shock locus v), which is encoded by 1 gene in bacteria, to the eukaryotic 20S proteasome, which is encoded by more than 14 genes [1]. Recently evidence of two novel groups of bacterial proteasomes was proposed. The first is Anbu, which is sparsely distributed among cyanobacteria and proteobacteria [1]. The second is call beta-proteobacteria proteasome homologue (BPH) [1].

Literature references

Valas RE, Bourne PE; , J Mol Evol. 2008;66:494-504.: Rethinking proteasome evolution: two novel bacterial proteasomes. PUBMED:18389302

InterPro entry IPR001353

The proteasome (or macropain) () PUBMED:7682410, PUBMED:2643381, PUBMED:1317508, PUBMED:7697118, PUBMED:8882582 is a eukaryotic and archaeal multicatalytic proteinase complex that seems to be involved in an ATP/ubiquitin-dependent nonlysosomal proteolytic pathway. In eukaryotes the proteasome is composed of about 28 distinct subunits which form a highly ordered ring-shaped structure (20S ring) of about 700 kDa. Most proteasome subunits can be classified, on the basis on sequence similarities into two groups, alpha (A) and beta (B).

ATP-dependent protease complexes are present in all three kingdoms of life, where they rid the cell of misfolded or damaged proteins and control the level of certain regulatory proteins. They include the proteasome in Eukaryotes, Archaea, and Actinomycetales and the HslVU (ClpQY, clpXP) complex in other eubacteria. Genes homologous to eubacterial HslV (ClpQ) and HslU (ClpY, clpX) have also been demonstrated in to be present in the genome of trypanosomatid protozoa PUBMED:12446803.

The prokaryotic ATP-dependent proteasome is coded for by the heat-shock locus VU (HslVU). It consists of HslV, the protease (MEROPS peptidase subfamily T1B), and HslU, , the ATPase and chaperone belonging to the AAA/Clp/Hsp100 family. The crystal structure ofThermotoga maritima HslV has been determined to 2.1-A resolution. The structure of the dodecameric enzyme is well conserved compared to those from Escherichia coli and Haemophilus influenzae PUBMED:12646382, PUBMED:12823960.

This entry contains threonine peptidases and non-peptidase homologs belong to MEROPS peptidase family T1 (proteasome family, clan PB(T)). The family consists of the protease components of the archaeal and bacterial proteasomes and the alpha and beta subunits of the eukaryotic proteasome.

Clan

This family is a member of clan NTN (CL0052), which contains the following 10 members:

AAT Asparaginase_2 CBAH DUF833 G_glu_transpept GATase_2 Penicil_amidase Peptidase_C69 Phospholip_B Proteasome

Gene Ontology

Cellular component	proteasome core complex (GO:0005839)
Molecular function	threonine-type endopeptidase activity (GO:0004298)
Biological process	proteolysis involved in cellular protein catabolic process (GO:0051603)

External database links

HOMSTRAD:	proteasome
MEROPS:	T1
PANDIT:	PF00227
PRINTS:	PR00141
PROSITE:	PDOC00326 PDOC00668
SCOP:	1pma
SYSTERS:	Proteasome

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 (175) Full (5013) NCBI (8038) Metagenomics (2216)
Viewer:

Formatting options

Alignment:	Seed (175) Full (5013)
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 (175) Full (5013) NCBI (8038) Metagenomics (2216)
Full length sequences	Full-sequences (5013)

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:

Prosite

Previous IDs:

proteasome;

Type:

Domain

Author:

Finn RD, Bateman A, Valas RE

Number in seed:

175

Number in full:

5013

Average length of the domain:

174.40 aa

Average identity of full alignment:

21 %

Average coverage of the sequence by the domain:

75.54 %

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	21.5	21.5
Trusted cut-off	21.5	21.5
Noise cut-off	21.4	21.4

Model length:

190

Family (HMM) version:

19

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
save a plain text representation of the tree

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Interactions

There are 3 interactions for this family. More...

Proteasome Proteasome_A_N AAA_2

Structures

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 Proteasome domain has been found.

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Family: Proteasome (PF00227)

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