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159  structures 103  species 1  interaction 2104  sequences 50  architectures

Family: MBT (PF02820)

Summary: mbt repeat

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mbt repeat Provide feedback

The function of this repeat is unknown, but is found in a number of nuclear proteins such as drosophila sex comb on midleg protein Q9VHA0. The repeat is found in up to four copies as in Q9UHJ3. The repeat contains a completely conserved glutamate at its amino terminus that may be important for function.

Literature references

  1. Bornemann D, Miller E, Simon J; , Genetics 1998;150:675-686.: Expression and properties of wild-type and mutant forms of the Drosophila sex comb on midleg (SCM) repressor protein. PUBMED:9755199 EPMC:9755199


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR004092

The function of the malignant brain tumor (MBT) repeat is unknown, but is found in a number of nuclear proteins involved in transcriptional repression. The repeat contains a completely conserved glutamate at its amino terminus that may be important for function.

The crystal structure of the two MBT repeats of human SCM-like 2 protein has been reported. Each repeat consists of an extended "arm" and a globular core. The arm of the first repeat packs against the core of the second repeat and vice versa. The structure of the core-interacting part of each arm consists of an N-terminal alpha-helix and a turn of 310 helix connected by a short beta-strand. The core consists of an Src homology 3-like five-stranded beta-barrel followed by a C-terminal alpha-helix and another short beta-strand. Each arm interacts with its partner core in a similar way, with the orientation of the N-terminal helix relative to the barrel varying slightly. There are also extensive interactions between the two barrels [PUBMED:12952983].

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 Tudor (CL0049), which has the following description:

This clan covers the Tudor domain 'royal family' [1]. This includes chromo, MBT, PWWP and tudor domains. The chromo domain is a comprised of approximately 50 amino acid residues. There are usually one to three Chromo domains found in a single protein. In some chromo domain containing proteins, a second related chromo domain has been found and is referred to as the Chromo-shadow domain. The structure of the Chromo and Chromo-shadow domains reveal an OB-fold, a fold found in a variety of prokaryotic and eukaryotic nucleic acid binding proteins. More specifically,the chromo-domain structure reveals a three beta strands that are packed against an alpha helix. Interestingly, a similar structure is found in the archaeal chromatin proteins (7kDa DNA-binding domain). These are sequence neutral DNA binding proteins. The DNA binding in these archaeal proteins is mediated through the triple stranded beta sheet. These archaeal domains are though to represent an ancestral chromo domain. Homologs of the chromo domain have been found in fission yeast, ciliated protozoa and all animal species, but appear to be absent in eubacteria, budding yeast and plants [2]. The precise function of the chromo domain is unclear, but the chromo domain is thought to act as a targeting module for chromosomal proteins, although the chromosomal contexts and functional contexts being targeted vary. In all cases studies, the chromo domains are found in proteins that are involved in transcription regulation, positive and negative [2].

The clan contains the following 14 members:

53-BP1_Tudor 7kD_DNA_binding Agenet Chromo Chromo_shadow DUF1325 DUF4537 MBT PWWP Rad9_Rad53_bind RBB1NT SMN TUDOR Tudor-knot

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
(18)
Full
(2104)
Representative proteomes NCBI
(1975)
Meta
(0)
RP15
(218)
RP35
(298)
RP55
(671)
RP75
(1180)
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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
(18)
Full
(2104)
Representative proteomes NCBI
(1975)
Meta
(0)
RP15
(218)
RP35
(298)
RP55
(671)
RP75
(1180)
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
(18)
Full
(2104)
Representative proteomes NCBI
(1975)
Meta
(0)
RP15
(218)
RP35
(298)
RP55
(671)
RP75
(1180)
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.

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: Pfam-B_526 (Release 6.2)
Previous IDs: mbt;
Type: Family
Author: Bateman A
Number in seed: 18
Number in full: 2104
Average length of the domain: 72.60 aa
Average identity of full alignment: 33 %
Average coverage of the sequence by the domain: 29.03 %

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 20.2 20.2
Trusted cut-off 20.3 20.6
Noise cut-off 20.1 19.9
Model length: 73
Family (HMM) version: 13
Download: download the raw HMM for this family

Species distribution

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Interactions

There is 1 interaction for this family. More...

MBT

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 MBT domain has been found. There are 159 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.

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