Cholera toxin: Difference between revisions
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[[Cholera toxin]] (CTX), secreted by bacterium [http://en.wikipedia.org/wiki/Vibrio_cholerae Vibrio Cholerae],is an oligomeric complex of enzymatic A and pentameric B subunits, which bind to the cell surface. CTX is the main cause of the diarrhea symptoms of cholera infection. | [[Cholera toxin]] (CTX), secreted by bacterium [http://en.wikipedia.org/wiki/Vibrio_cholerae Vibrio Cholerae],is an oligomeric complex of enzymatic A and pentameric B subunits, which bind to the cell surface. CTX is the main cause of the diarrhea symptoms of cholera infection. | ||
== Structure == | == Structure == | ||
[[Image:CTX interaction.PNG|left|270px|thumb| Interaction of 7 chains of Cholera toxin[[1xtc]]. Cholera toxin contains 7 chains: A,C,D,E,F,G and H.Chains A and C belong to subunit A. Chains C,D,E,F,G and H belong to subunit B]] | [[Image:CTX interaction.PNG|left|270px|thumb| Interaction of 7 chains of Cholera toxin [[1xtc]]. Cholera toxin contains 7 chains: A,C,D,E,F,G and H.Chains A and C belong to subunit A. Chains C,D,E,F,G and H belong to subunit B]] | ||
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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 is the main virulence factor of the pathogen ''Vibrio cholerae'' and cause the major symptom of infection: extreme diarrhea, vomiting, cramps and even death <ref>Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. p. 375. ISBN 0838585299.</ref>,<ref>Faruque SM; Nair GB (editors). (2008). Vibrio cholerae: Genomics and Molecular Biology. Caister Academic Press. ISBN 978-1-904455-33-2.</ref>,<ref>Jennifer McDowall, Cholera Toxin, EMBL-EMI, Interpro</ref>. | 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 is the main virulence factor of the pathogen ''Vibrio cholerae'' and cause the major symptom of infection: extreme diarrhea, vomiting, cramps and even death <ref>Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. p. 375. ISBN 0838585299.</ref>,<ref>Faruque SM; Nair GB (editors). (2008). Vibrio cholerae: Genomics and Molecular Biology. Caister Academic Press. ISBN 978-1-904455-33-2.</ref>,<ref>Jennifer McDowall, Cholera Toxin, EMBL-EMI, Interpro</ref>. | ||
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)[http://en.wikipedia.org/wiki/ADP_ribosylation_factor], enabling its catalytic activity. | 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)[http://en.wikipedia.org/wiki/ADP_ribosylation_factor], enabling its catalytic activity. | ||
[[Image:1xtc.png|right|280px|thumb|Crystal Structure of Cholera toxin [[1xtc]]]] | [[Image:1xtc.png|right|280px|thumb|Crystal Structure of Cholera toxin [[1xtc]]]] | ||
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**[[1tet]] – CTX peptide 3+FAB light and heavy chains - mouse | **[[1tet]] – CTX peptide 3+FAB light and heavy chains - mouse | ||
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== See also [[Toxins]] == | |||
== Multiple Sequence Alignment == | == Multiple Sequence Alignment == | ||
[[Image:MSA1.jpg|left|250px|thumb|Multiple Sequence Alignment-TEXSHADE result.BlastP of CTX A subunit that contains six different species. This is made by Biology Workbench]] | [[Image:MSA1.jpg|left|250px|thumb|Multiple Sequence Alignment-TEXSHADE result.BlastP of CTX A subunit that contains six different species. This is made by Biology Workbench]] | ||