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| | <StructureSection load='1ct1' size='340' side='right'caption='[[1ct1]], [[Resolution|resolution]] 2.30Å' scene=''> | | <StructureSection load='1ct1' size='340' side='right'caption='[[1ct1]], [[Resolution|resolution]] 2.30Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[1ct1]] is a 5 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CT1 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1CT1 FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[1ct1]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Vibrio_cholerae Vibrio cholerae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CT1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1CT1 FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GAL:BETA-D-GALACTOSE'>GAL</scene>, <scene name='pdbligand=NGA:N-ACETYL-D-GALACTOSAMINE'>NGA</scene>, <scene name='pdbligand=SIA:O-SIALIC+ACID'>SIA</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.3Å</td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ct1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ct1 OCA], [http://pdbe.org/1ct1 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1ct1 RCSB], [http://www.ebi.ac.uk/pdbsum/1ct1 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1ct1 ProSAT]</span></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GAL:BETA-D-GALACTOSE'>GAL</scene>, <scene name='pdbligand=NGA:N-ACETYL-D-GALACTOSAMINE'>NGA</scene>, <scene name='pdbligand=SIA:O-SIALIC+ACID'>SIA</scene></td></tr> |
| | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1ct1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ct1 OCA], [https://pdbe.org/1ct1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ct1 RCSB], [https://www.ebi.ac.uk/pdbsum/1ct1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ct1 ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/CHTB_VIBCH CHTB_VIBCH]] 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 can bind five GM1 gangliosides. It has no toxic activity by itself. | + | [https://www.uniprot.org/uniprot/CHTB_VIBCH CHTB_VIBCH] 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 can bind five GM1 gangliosides. It has no toxic activity by itself. |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | </StructureSection> | | </StructureSection> |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Hol, W G.J]] | + | [[Category: Vibrio cholerae]] |
| - | [[Category: Merritt, E A]] | + | [[Category: Hol WGJ]] |
| - | [[Category: Enterotoxin]] | + | [[Category: Merritt EA]] |
| - | [[Category: Oligosaccharide]]
| + | |
| - | [[Category: Toxin-receptor complex]]
| + | |
| Structural highlights
1ct1 is a 5 chain structure with sequence from Vibrio cholerae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Method: | X-ray diffraction, Resolution 2.3Å |
| Ligands: | , , , , |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
CHTB_VIBCH 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 can bind five GM1 gangliosides. It has no toxic activity by itself.
Publication Abstract from PubMed
The wide range of receptor binding affinities reported to result from mutations at residue Gly 33 of the cholera toxin B-pentamer (CTB) has been most puzzling. For instance, introduction of an aspartate at this position abolishes receptor binding, whereas substitution by arginine retains receptor affinity despite the larger side chain. We now report the structure determination and 2.3-A refinement of the CTB mutant Gly 33-->Arg complexed with the GM1 oligosaccharide, as well as the 2.2-A refinement of a Gly 33-->Asp mutant of the closely related Escherichia coli heat-labile enterotoxin B-pentamer (LTB). Two of the five receptor binding sites in the Gly 33-->Arg CTB mutant are occupied by bound GM1 oligosaccharide; two other sites are involved in a reciprocal toxin:toxin interaction; one site is unoccupied. We further report a higher resolution (2.0 A) determination and refinement of the wild-type CTB:GM1 oligosaccharide complex in which all five oligosaccharides are seen to be bound in essentially identical conformations. Saccharide conformation and binding interactions are very similar in both the CTB wild-type and Gly 33-->Arg mutant complexes. The protein conformation observed for the binding-deficient Gly 33-->Asp mutant of LTB does not differ substantially from that seen in the toxin:saccharide complexes. The critical nature of the side chain of residue 33 is apparently due to a limited range of subtle rearrangements available to both the toxin and the saccharide to accommodate receptor binding. The intermolecular interactions seen in the CTB (Gly 33-->Arg) complex with oligosaccharide suggest that the affinity of this mutant for the receptor is close to the self-affinity corresponding to the toxin:toxin binding interaction that has now been observed in crystal structures of three CTB mutants.
Structural studies of receptor binding by cholera toxin mutants.,Merritt EA, Sarfaty S, Jobling MG, Chang T, Holmes RK, Hirst TR, Hol WG Protein Sci. 1997 Jul;6(7):1516-28. PMID:9232653[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Merritt EA, Sarfaty S, Jobling MG, Chang T, Holmes RK, Hirst TR, Hol WG. Structural studies of receptor binding by cholera toxin mutants. Protein Sci. 1997 Jul;6(7):1516-28. PMID:9232653
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