Summary: TonB C terminal
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TonB C terminal Provide feedback
This family contains TonB members that are not captured by PF03544.
Internal database links
|Similarity to PfamA using HHSearch:||TonB_C TolA|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR006260
TonB interacts with outer membrane receptor proteins that carry out high-affinity binding and energy dependent uptake into the periplasmic space of specific substrates such as cobalamin, and various iron compounds [PUBMED:16741124, PUBMED:9643536]. B-12 and colicin receptors also make use of the tonB system to drive active transport at the outer membrane [PUBMED:21455261].
This C-terminal domain is characteristic of TonB and its homologues. Most members are designated as TonB or TonB-related proteins, but a few represent the paralogous TolA protein. Several bacteria have up to four TonB paralogs. In nearly every case, a proline-rich repetitive region is found N-terminal to this domain; this low-complexity region is highly divergent and is suggested to span the periplasm. The TolA and TonB C-terminal domains adopt a structure containing anti-parallel beta sheets with some alpha helical regions. TolA contains an extra N-terminal helix over the common fold [PUBMED:15644214].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||membrane (GO:0016020)|
|outer membrane-bounded periplasmic space (GO:0030288)|
|Molecular function||protein transporter activity (GO:0008565)|
|Biological process||protein transport (GO:0015031)|
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This clan contains the TolA and TonB C terminal domains. These domains adopt a structure containing anti-parallel beta sheets with some alpha helical regions. The TolA family contains an extra N-terminal helix over the common fold, and the TonB is an isolated domain that can form different segment-swapped dimers depending on the fragment length .
The clan contains the following 3 members:TolA TonB_2 TonB_C
We make a range of alignments for each Pfam-A family:
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Curation and family details
|Number in seed:||102|
|Number in full:||1325|
|Average length of the domain:||85.30 aa|
|Average identity of full alignment:||19 %|
|Average coverage of the sequence by the domain:||30.22 %|
|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:||1|
|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 TonB_2 domain has been found. There are 1 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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