Summary: TcdA/TcdB catalytic glycosyltransferase domain
TcdA/TcdB catalytic glycosyltransferase domain Provide feedback
This domain represents the N-terminal glycosyltransferase from a set of toxins found in some bacteria. This domain in TcdB glycosylates the host RhoA protein.
Internal database links
|Similarity to PfamA using HHSearch:||Gly_transf_sug|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR024770
Toxins A (TcdA) and B (TcdB) of Clostridium difficile belong to the family of clostridial glucosylating toxins. These toxins glucosylate small GTPases of Rho and Ras families, inhibiting the signalling and regulatory functions of these switch proteins. After receptor-binding, the toxins are endocytosed to reach acidic endosomal compartments from where the toxins are translocated into the cytosol [PUBMED:20498856].
TcdB has been shown to consist of a N-terminal glucosyltransferase domain (GTD), responsible for the biological effects of the toxin, a cysteine protease domain (CPD), responsible for autocatalytic cleavage, a hydrophobic region (HR), which has been suggested to be involved in toxin translocation, and a C-terminal repetitive domain involved in receptor binding. The pore-forming region of toxin B has been described to be in a region in the middle of the protein, within amino acid residues 830 and 990 [PUBMED:21231971].
This entry represents the N-terminal glucosyltransferase domain from TcdA and TcdB. It is also found in other toxins. The GTD of TcdB has been shown to glycosylate the host's RhoA protein [PUBMED:16054646].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||transferase activity, transferring glycosyl groups (GO:0016757)|
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- the UniProt description of the protein sequence
- the number of residues in the sequence
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This is the GT-A clan that contains diverse glycosyltransferases that possess a Rossmann like fold .
The clan contains the following 44 members:Anp1 Caps_synth Cellulose_synt CgtA CHGN Chitin_synth_1 Chitin_synth_2 CofC CTP_transf_3 DUF2064 DUF273 DUF604 Fringe Galactosyl_T GlcNAc Gly_transf_sug Glyco_tranf_2_2 Glyco_tranf_2_3 Glyco_tranf_2_4 Glyco_tranf_2_5 Glyco_trans_2_3 Glyco_transf_21 Glyco_transf_25 Glyco_transf_34 Glyco_transf_43 Glyco_transf_49 Glyco_transf_6 Glyco_transf_64 Glyco_transf_7C Glyco_transf_7N Glyco_transf_8 Glyco_transf_92 Glycos_transf_2 GNT-I IspD Mannosyl_trans3 MGAT2 NTP_transf_3 NTP_transferase Nucleotid_trans Pox_P35 Rhamno_transf TcdA_TcdB UDPGP
We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
- the alignment generated by searching the sequence database using the HMM
- Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
- alignment generated by searching the NCBI sequence database using the family HMM
- alignment generated by searching the metagenomics sequence database using the family HMM
You can see the alignments as HTML or in three different sequence viewers:
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Curation and family details
|Seed source:||Bateman A|
|Number in seed:||14|
|Number in full:||376|
|Average length of the domain:||327.40 aa|
|Average identity of full alignment:||31 %|
|Average coverage of the sequence by the domain:||26.98 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||2|
|Download:||download the raw HMM for this family|
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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 TcdA_TcdB domain has been found. There are 14 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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