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22  structures 37  species 0  interactions 78  sequences 27  architectures

Family: GbpC (PF08363)

Summary: Glucan-binding protein C

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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.

Glucan-binding protein C Provide feedback

This domain is found in the Streptococcus Glucan-binding protein C (GbpC) and also in surface protein antigen (Spa)-family proteins which show sequence similarity to GbpC [1].

Literature references

  1. Sato Y, Yamamoto Y, Kizaki H; , Infect Immun 1997;65:668-675.: Cloning and sequence analysis of the gbpC gene encoding a novel glucan-binding protein of Streptococcus mutans. PUBMED:9009329 EPMC:9009329

This tab holds annotation information from the InterPro database.

InterPro entry IPR013574

This domain is found in glucan-binding protein C (GbpC) and in the V-region of surface protein antigen; both these proteins belong to the Spa family of Streptococcal proteins [ PUBMED:9009329 ]. This domain consists of a beta-supersandwich of 18 beta-strands in two sheets.

There are at least four types of glucan-binding proteins (Gbp) in Streptococcus mutans, GbpA, GbpB, GbpC and GbpD. These proteins promote the adhesion of Streptococcal bacteria to teeth and are associated with dental caries [ PUBMED:17241168 ]. GbpC is a cell-wall anchoring protein that plays an important role in sucrose-dependent adhesion by binding to soluble glucan synthesised by glucosyltransferase D (GTFD) [ PUBMED:16390340 ].

Spa antigens I/II are multi-functional proteins expressed at the cell wall surface of oral Streptococci, where they function as adhesins. Antigens I/II recognise a wide range of ligands. They exert an immunomodulatory effect on human cells and are important in inflammatory disorders, such as dental caries. These proteins can be divided into seven regions: signal peptide, N-terminal, A-region (alanine-rich), V-region (variable domain), P-region (proline-rich), C-terminal domain, and a cell wall anchor motif. The V-region is the central domain and exhibits the greatest variability in sequence, and is responsible for binding monocyte receptors, its binding stimulating the release of TNF-alpha from the monocytes. The crystal structure of the V-region revealed a lectin-like fold that displays a putative preformed carbohydrate-binding site stabilised by a metal ion [ PUBMED:12054777 ].

Domain organisation

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

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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 (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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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.

Representative proteomes UniProt
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Representative proteomes UniProt

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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.

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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

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...


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_3074 (release 18.0)
Previous IDs: none
Type: Family
Sequence Ontology: SO:0100021
Author: Wuster A
Number in seed: 5
Number in full: 78
Average length of the domain: 227.2 aa
Average identity of full alignment: 24 %
Average coverage of the sequence by the domain: 24.41 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 27.2 27.2
Trusted cut-off 48.0 42.1
Noise cut-off 22.6 23.8
Model length: 300
Family (HMM) version: 13
Download: download the raw HMM for this family

Species distribution

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Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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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...

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


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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 GbpC domain has been found. There are 22 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 sequence.

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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
A8AUS0 View 3D Structure Click here
A8AUS1 View 3D Structure Click here
P17953 View 3D Structure Click here
P23504 View 3D Structure Click here