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Bacterial enterotoxins superfamily
SCOP classification
Superfamily statistics
Functional annotation
General category | Processes_EC |
Detailed category | Toxins/defense |
Document: Function annotation of SCOP domain superfamilies
InterPro annotation
Cross references | IPR008992 SSF50203 Protein matches |
Abstract | Cholera toxin produced by Vibrio cholerae and heat-labile enterotoxin, produced by enterotoxigenic Escherichia coli, are AB5 heterohexamers, consisting of one A polypeptide and five identical B polypeptides, with an ADP-ribosylating A subunit and a GM1 receptor binding B pentamer. These toxins are among the most potent mucosal adjuvants known. The B pentamer is required for binding to the cell surface receptor ganglioside GM1. The A subunit can be proteolytically cleaved within the single disulphide-linked loop between two cysteine residues to produce the enzymatically active A1 polypeptide and the smaller A2 polypeptide that links fragment A1 to the B pentamer. Upon entry into enterocytes by endocytosis and following reduction and translocation, CT-A1 ADP-ribosylates a regulatory G-protein (Gsalpha), which leads to constitutive activation of adenylate cyclase, increased intracellular concentration of cyclic AMP, and secretion of fluid and electrolytes into the lumen of the small intestine [11395467].
All family members contain a common OB-fold, a five-stranded beta-sheet coiled to form a closed beta-barrel capped by an alpha-helix located between the third and fourth strands. |
InterPro database
PDBeMotif information about ligands, sequence and structure motifs
PDBeMotif resource
Jump to [ Top of page · SCOP classification · InterPro annotation · PDBeMotif links · Functional annotation ]
Internal database links
Browse genome assignments for this superfamily. The SUPERFAMILY hidden Markov model library has been used to carry
out SCOP domain assignments to all genomes at the superfamily level.
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Alignments of sequences to 41 models
in this superfamily are available by clicking on the 'Alignments' icon above. PDB sequences less than 40% identical
are shown by default, but any other sequence(s) may be aligned. Select PDB sequences, genome sequences, or paste in or upload your own sequences.
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Browse and view proteins in genomes which have
different domain combinations including a Bacterial enterotoxins domain.
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Examine the distribution of domain superfamilies, or families, across the major taxonomic kingdoms or genomes within a kingdom. This gives an immediate impression of how superfamilies, or families, are restricted to certain kingdoms of life.
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Explore domain occurrence network where nodes represent genomes and edges are domain architectures (shared between genomes) containing the superfamily of interest.
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There are 41 hidden Markov models representing the Bacterial enterotoxins superfamily. Information on how the models are built, and plots showing hydrophobicity, match emmission probabilities and insertion/deletion probabilities can be inspected.
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Jump to [ Top of page · SCOP classification · InterPro annotation · PDBeMotif links · Functional annotation · Internal database links ]
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