Summary

RNA polymerase beta subunit external 1 domain

RNA polymerases catalyse the DNA-dependent polymerisation of RNA. Prokaryotes contain a single RNA polymerase compared with three in eukaryotes (not including mitochondrial or chloroplast polymerases). This domain in prokaryotes spans the gap between domains 4 and 5 of the yeast protein. It is also known as the external 1 region of the polymerase and is bound in association with the external 2 region [1].

Literature references

Cramer P, Bushnell DA, Kornberg RD; , Science 2001;292:1863-1876.: Structural basis of transcription: RNA polymerase II at 2.8 angstrom resolution. PUBMED:11313498

InterPro entry IPR019462

DNA-directed RNA polymerases (also known as DNA-dependent RNA polymerases) are responsible for the polymerisation of ribonucleotides into a sequence complementary to the template DNA. In eukaryotes, there are three different forms of DNA-directed RNA polymerases transcribing different sets of genes. Most RNA polymerases are multimeric enzymes and are composed of a variable number of subunits. The core RNA polymerase complex consists of five subunits (two alpha, one beta, one beta-prime and one omega) and is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme PUBMED:3052291. The core RNA polymerase complex forms a "crab claw"-like structure with an internal channel running along the full length PUBMED:10499798. The key functional sites of the enzyme, as defined by mutational and cross-linking analysis, are located on the inner wall of this channel.

RNA synthesis follows after the attachment of RNA polymerase to a specific site, the promoter, on the template DNA strand. The RNA synthesis process continues until a termination sequence is reached. The RNA product, which is synthesised in the 5' to 3'direction, is known as the primary transcript. Eukaryotic nuclei contain three distinct types of RNA polymerases that differ in the RNA they synthesise:

RNA polymerase I: located in the nucleoli, synthesises precursors of most ribosomal RNAs.
RNA polymerase II: occurs in the nucleoplasm, synthesises mRNA precursors.
RNA polymerase III: also occurs in the nucleoplasm, synthesises the precursors of 5S ribosomal RNA, the tRNAs, and a variety of other small nuclear and cytosolic RNAs.

Eukaryotic cells are also known to contain separate mitochondrial and chloroplast RNA polymerases. Eukaryotic RNA polymerases, whose molecular masses vary in size from 500 to 700 kD, contain two non-identical large (>100 kDa) subunits and an array of up to 12 different small (less than 50 kDa) subunits.

RNA polymerases catalyse the DNA-dependent polymerisation of RNA. Prokaryotes contain a single RNA polymerase compared with three in eukaryotes (not including mitochondrial or chloroplast polymerases). This entry represents a domain in prokaryotic polymerases that spans the gap between domains 4 and 5 of the protein. It is also known as the external 1 region of the polymerase and is bound in association with the external 2 region PUBMED:11313498.

Gene Ontology

Molecular function	DNA-directed RNA polymerase activity (GO:0003899)
Biological process	transcription, DNA-dependent (GO:0006351)

External database links

PANDIT:	PF10385
SYSTERS:	RNA_pol_Rpb2_45

Domain organisation

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

Loading domain graphics...

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 (149) Full (4216) NCBI (7487) Metagenomics (2367)
Viewer:

Formatting options

Alignment:	Seed (149) Full (4216)
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 (149) Full (4216) NCBI (7487) Metagenomics (2367)
Full length sequences	Full-sequences (4216)

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:

Gene3D, pdb_2a6h

Previous IDs:

none

Type:

Domain

Author:

Coggill PC

Number in seed:

149

Number in full:

4216

Average length of the domain:

65.60 aa

Average identity of full alignment:

45 %

Average coverage of the sequence by the domain:

9.56 %

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:

66

Family (HMM) version:

2

Download:

download the raw HMM for this family

Species distribution

Tree controls

Hide

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

Loading...

Interactions

There are 6 interactions for this family. More...

RNA_pol_Rpb1_5 RNA_pol_Rpb2_6 RNA_pol_Rpb2_1 RNA_pol_Rpb2_2 RNA_pol_Rpb2_3 RNA_pol_Rpb1_4

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 RNA_pol_Rpb2_45 domain has been found.

Loading structure mapping...

Family: RNA_pol_Rpb2_45 (PF10385)

Jump to...