1XTC | Toxin | date | Jan 10, 1996 ![]() |
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title | Cholera Toxin | ||||||||||||||
authors | R.-G.Zhang, E.Westbrook | ||||||||||||||
compound | source | ||||||||||||||
Molecule: Cholera Toxin Chain: A, C, D, E, E, F, G, H Synonym: Ctx, Choleragen |
Organism_scientific: Vibrio Cholerae Organism_common: Vibrio Strain: 569b Other_details: Commercially Obtained From List Biological Laboratory, Campber Ca95008 | ||||||||||||||
symmetry | Space Group: P 1 21 1 | R_factor | 0.185 | ||||||||||||
crystal cell |
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method | X-Ray Diffraction | resolution | 2.4 Å | ||||||||||||
note | 1XTC (Molecule of the Month:pdb69) | ||||||||||||||
domain | The four c-terminal residues of the a2 chain occupy the central pore of the holotoxin. Deletion of this residues weakens the interaction between the a subunit and the b pentamer whithout impairing the pentamer formation. | ||||||||||||||
similarity | Belongs to the Enterotoxin_b family. | ||||||||||||||
subunit | The a subunit contains two chains, a1 and a2, linked by a disulfide bridge. The holotoxin (choleragen) consists of a pentameric ring of b subunits whose central pore is occupied by the a subunit. | ||||||||||||||
catalytic activ. | Nad(+) + peptide diphthamide = nicotinamide + peptide n-(adp-d-ribosyl)diphthamide. | ||||||||||||||
genes | ctxA, ctxB (V. cholerae) | ||||||||||||||
function | This leads to an overproduction of camp and eventually to a hypersecretion of chloride and bicarbonate followed by water, resulting in the characteristic cholera stool. The a2 chain tethers a1 to the pentameric ring. The a1 chain catalyzes the adp-ribosylation of gs alpha, a gtp-binding regulatory protein, to activate the adenylate cyclase. It can bind five gm1 gangliosides. The b subunit pentameric ring directs the a subunit to its target by binding to the gm1 gangliosides present on the surface of the intestinal epithelial cells. It has no toxic activity by itself. | ||||||||||||||
Gene Ontology |
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Primary reference | The three-dimensional crystal structure of cholera toxin., Zhang RG, Scott DL, Westbrook ML, Nance S, Spangler BD, Shipley GG, Westbrook EM, J Mol Biol 1995 Aug 25;251(4):563-73. PMID:7658473 |
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Structure-derived information |
- Domain d1xtc.1, region A:,C [Jmol] [rasmolscript] [script source] - Domain d1xtcd_, region D [Jmol] [rasmolscript] [script source] - Domain d1xtce_, region E [Jmol] [rasmolscript] [script source] - Domain d1xtcf_, region F [Jmol] [rasmolscript] [script source] - Domain d1xtcg_, region G [Jmol] [rasmolscript] [script source] - Domain d1xtch_, region H [Jmol] [rasmolscript] [script source] |
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