OCA Atlas for 1CHQ

1CHQ

Toxin

date

Feb 15, 1995

authors

E.A.Merritt, W.G.J.Hol

compound

source

Molecule: Cholera Toxin B Pentamer
Chain: D, E, F, G, H
Synonym: Choleragen
Engineered: Yes
Mutation: R35d

Organism_scientific: Vibrio Cholerae
Strain: Ogawa 41 (Classical)
Expression_system: Escherichia Coli

symmetry

Space Group: C 2

R_factor

crystal
cell

length a	length b	length c	angle alpha	angle beta	angle gamma
102.600	67.390	98.810	90.00	131.63	90.00

method

X-Ray Diffraction

resolution

2.1 Å

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.

gene

ctxB (V. cholerae)

function

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

Chain	Function	Process	Component
H, F, D, G, E		pathogenesis	extracellular region membrane

Primary reference

Surprising leads for a cholera toxin receptor-binding antagonist: crystallographic studies of CTB mutants., Merritt EA, Sarfaty S, Chang TT, Palmer LM, Jobling MG, Holmes RK, Hol WG, Structure 1995 Jun 15;3(6):561-70. PMID:8590017

Data retrieval

Asymmetric unit, PDB entry: [header only] [complete with coordinates] (105 Kb) [Save to disk]

Biological Unit Coordinates (1chq.pdb1.gz) 84 Kb

CSU: Contacts of Structural Units for 1CHQ

Likely Quarternary Molecular Structure file(s) for 1CHQ

Structure Factors (306 Kb)

Retrieve 1CHQ in mmCIF format [Save to disk]

View 1CHQ in 3D

On Jmol, a nice Rasmol like molecule viewer. This is good for easiest viewing of basic structure.

On FirstGlance, an excellent tool for a guided tour on the structure components, by E. Martz.

On AstexViewer, from MSD-EBI (viewer documentation).

On RasMol (Install RasMol freeware) Here's help on how to use RasMol.

Visual 3D analysis of 1CHQ

Protein Explorer, Easier to use and more powerful than RasMol. (Win and Mac only)

Noncovalent Bond Finder displays the closest contacts to ligand or interface, reports distances, walks over water bridges.

STING, shows the sequence and maps the locations of sequence residues or residue ranges onto the 3D structure.

GRASS (Graphical Representation and Analysis of Structure Server)

Cartoon representation from PDB Cartoon

Ramachandran plot from PDBSum

Structure-derived information

Electron Density related parameters from EDS Electron Density Server, at Upsala

Dipole moment, from Dipole Server at Weizmann Institute

Crystal Contacts, from CryCo at Weizmann Institute

3D motif for 1CHQ, from MSDmotif at EBI

Genome occurence of 1CHQ's fold from GeneCensus

Classification of representative domains in scop (Structural Classification of Proteins)
- Domain d1chqd_, region D [Jmol] [rasmolscript] [script source]
- Domain d1chqe_, region E [Jmol] [rasmolscript] [script source]
- Domain d1chqf_, region F [Jmol] [rasmolscript] [script source]
- Domain d1chqg_, region G [Jmol] [rasmolscript] [script source]
- Domain d1chqh_, region H [Jmol] [rasmolscript] [script source]

Fold representative 1chq from FSSP and Dali (Families of Structurally Similar Proteins)

Class (fold), Architecture (subfold), Topology, Homologous superfamily from CATH

Summaries and structural analyses of PDB data files from PDBSum

Identification of Protein Pockets & Cavities at CASTp

Sequence-derived information

View one-letter amino acid or nucleotide sequence for each chain: [1chq_G] [1chq_H] [1chq_F] [1chq_D] [1chq_E]

Other resources with information on 1CHQ

InterPro: IPR001835

PDBREPORT (protein verification by WHAT_CHECK procedures)

MMDB (Entrez's Structure Database)

Movements, Movies and Images

Images from IMB Jena Image Library of Biological Macromolecules.

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