Please note: this site relies heavily on the use of javascript. Without a javascript-enabled browser, this site will not function correctly. Please enable javascript and reload the page, or switch to a different browser.
21  structures 536  species 2  interactions 2462  sequences 23  architectures

Family: TFIIB (PF00382)

Summary: Transcription factor TFIIB repeat

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

The Pfam group coordinates the annotation of Pfam families in Wikipedia, but we have not yet assigned a Wikipedia article to this family. If you think that a particular Wikipedia article provides good annotation, please let us know.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Transcription factor TFIIB repeat Provide feedback

No Pfam abstract.

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR013150

Cyclins are eukaryotic proteins that play an active role in controlling nuclear cell division cycles [PUBMED:12910258], and regulate cyclin dependent kinases (CDKs). Cyclins, together with the p34 (cdc2) or cdk2 kinases, form the Maturation Promoting Factor (MPF). There are two main groups of cyclins, G1/S cyclins, which are essential for the control of the cell cycle at the G1/S (start) transition, and G2/M cyclins, which are essential for the control of the cell cycle at the G2/M (mitosis) transition. G2/M cyclins accumulate steadily during G2 and are abruptly destroyed as cells exit from mitosis (at the end of the M-phase). In most species, there are multiple forms of G1 and G2 cyclins. For example, in vertebrates, there are two G2 cyclins, A and B, and at least three G1 cyclins, C, D, and E.

Cyclin homologues have been found in various viruses, including Saimiriine herpesvirus 2 (Herpesvirus saimiri) and Human herpesvirus 8 (HHV-8) (Kaposi's sarcoma-associated herpesvirus). These viral homologues differ from their cellular counterparts in that the viral proteins have gained new functions and eliminated others to harness the cell and benefit the virus [PUBMED:11056549].

In eukaryotes, transcription initiation of all protein encoding genes involves the polymerase II system. This sytem is modulated by both general and specific transcription factors. The general factors (which include TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIG and TFIIH) operate through common promoter elements, such as the TATA box. Transcription factor IIB (TFIIB) is of central importance in transcription of class II genes. It associates with TFIID-TFIIA bound to DNA (the DA complex) to form a ternary TFIID-IIA-IBB (DAB) complex, which is recognised by RNA polymerase II [PUBMED:1876184, PUBMED:1949150]. TFIIB comprises ~315-340 residues and contains an imperfect C-terminal repeat of a 75-residue domain that may contribute to the symmetry of the folded protein. The basal archaeal transcription machinery resembles that of the eukaryotic polymerase II system and includes a homologue of TFIIB [PUBMED:7597027].

This entry represents a cyclin-like domain which is found repeated in the C-terminal region of a variety of eukaryotic TFIIB's and their archaeal counterparts. These domains individually form the typical cyclin fold, and in the transcription complex they straddle the C-terminal region of the TATA-binding protein - an interaction essential for the formation of the transcription initiation complex [PUBMED:9177165, PUBMED:10619841].

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...

Loading domain graphics...

Pfam Clan

This family is a member of clan Cyclin (CL0065), which has the following description:

This Clan contains cyclins, Transcription factor IIB (TFIIB), and the Retinoblastoma tumour suppressor proteins. These were predicted to be related by sequence [1].

The clan contains the following 7 members:

CDK5_activator Cyclin Cyclin_C Cyclin_N RB_A RB_B TFIIB

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...

View options

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
(12)
Full
(2462)
Representative proteomes NCBI
(2387)
Meta
(745)
RP15
(455)
RP35
(879)
RP55
(1280)
RP75
(1522)
Jalview View  View  View  View  View  View  View  View 
HTML View  View  View  View  View  View     
PP/heatmap 1 View  View  View  View  View     
Pfam viewer View  View             

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

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

Format an alignment

  Seed
(12)
Full
(2462)
Representative proteomes NCBI
(2387)
Meta
(745)
RP15
(455)
RP35
(879)
RP55
(1280)
RP75
(1522)
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
(12)
Full
(2462)
Representative proteomes NCBI
(2387)
Meta
(745)
RP15
(455)
RP35
(879)
RP55
(1280)
RP75
(1522)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped 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.

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.

Pfam alignments:

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: Prosite
Previous IDs: transcript_fac2;
Type: Domain
Author: Finn RD
Number in seed: 12
Number in full: 2462
Average length of the domain: 70.60 aa
Average identity of full alignment: 26 %
Average coverage of the sequence by the domain: 32.13 %

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 20.6 20.6
Trusted cut-off 20.6 20.6
Noise cut-off 20.5 20.5
Model length: 71
Family (HMM) version: 14
Download: download the raw HMM for this family

Species distribution

Sunburst controls

Show

This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

Loading sunburst data...

Tree controls

Hide

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

Loading...

Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.

Interactions

There are 2 interactions for this family. More...

TBP TFIIB

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 TFIIB domain has been found. There are 21 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

Loading structure mapping...