Cholera toxin

Cholera toxin (CTX) from the bacterium Vibrio cholerae is an oligomeric complex of an enzymatic subunit (chain A) and 5 copies of chain B which bind to the cell surface. Cholera toxin(CTX) has two types of subunits: subunit A and subunit B. A subunit contains A1 domain, which includes the enzymatic active site, and A2 domain, which has a α–helix tail. The B subunit contains five chains that form a pentameric ring around the central pore in structure; Subunit A and subunit B are assembled by the α–helix tail of A2 domain, which inserts into the central pore. CTX the main virulence factor of the pathogen Vibrio cholerae and cause the major symptom of infection: extreme diarrhea, vomiting, cramps and even death [1][2][3]. The enzymatic subunit has a globular domain (CTA1) and a long helical domain (CTA2). Once the CTX binds to the cell surface, it is internalized, and its CTA1 domain binds to ADP-ribosylation factor 6 (Arf6) enabling its catalytic activity. The images at the left and at the right correspond to the crystal structure of cholera toxin (1xtc). For toxins in Proteopedia see Toxins.

File:1xtc.png

Crystal Structure of Cholera toxin 1xtc

spinqualitylabelsall models PDB ID 1xtc Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
Cholera toxin 1xtc
Structural annotation: Resources: CATH : 1Xtca00, 1Xtcc00, 1Xtcd00, 1Xtce00, 1Xtcf00, 1Xtcg00, 1Xtch00 InterPro : Ipr000886, Ipr001144, Ipr008992, Ipr001835 Pfam : PF01375, PF01376 SCOP : d1xtc.1, d1xtcd_, d1xtce_, d1xtcf_, d1xtcg_, d1xtch_ UniProt : P01555, P01556
Functional annotation: Cellular component: extracellular region membrane Biological process: pathogenesis Molecular function: NAD+-diphthamide ADP-ribosyltransferase activity transferase activity, transferring glycosyl groups transferase activity catalytic activity
Evolutionary conservation: Toggle Conservation Colors: Rows = identical sequences: Further Information: Caveats, Explanation, Complete Results at ConSurfDB
Resources:	FirstGlance, OCA, RCSB, PDBsum
Coordinates:	save as pdb, mmCIF, xml

3D Structures of Cholera toxin3D Structures of Cholera toxin

Updated November 2011

CTXCTX

1xtc - CTX

CTX A subunitCTX A subunit

2a5d, 2a5g – CTX A subunit+hArf6+GTP – human
2a5f - CTX A subunit+hArf6+GTP+NAD
1s5b, 1s5c, 1s5d, 1s5e, 1s5f - CTX A subunit (mutant)

CTX B subunitsCTX B subunits

1fgb - CTX B subunits
1g8z , 1chp, 1chq - CTX B subunits (mutant)
1rcv, 1rd9, 1rdp, 1rf2, 1pzi, 1pzj, 1pzk, 1efi, 1eef, 1djr, 1eei – CTX B subunits+ galactoside derivatives
1llr, 1jqy, 1jr0, 1fd7, 1md2 - CTX B subunits+BMSC derivatives
1eef - CTX B subunits+PEPG
3chb, 2chb - CTX B subunits+pentasaccharide
1ct1 - CTX B subunits (mutant)+pentasaccharide
3efx – CTX B/heat-labile enterotoxin B chain
1tet – CTX peptide 3+FAB light and heavy chains - mouse