1G8Z

HIS57ALA MUTANT OF CHOLERA TOXIN B-PENATMER


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.179 

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This is version 1.4 of the entry. See complete history


Literature

A mutant cholera toxin B subunit that binds GM1- ganglioside but lacks immunomodulatory or toxic activity.

Aman, A.T.Fraser, S.Merritt, E.A.Rodigherio, C.Kenny, M.Ahn, M.Hol, W.G.Williams, N.A.Lencer, W.I.Hirst, T.R.

(2001) Proc Natl Acad Sci U S A 98: 8536-8541

  • DOI: 10.1073/pnas.161273098
  • Primary Citation of Related Structures:  
    1G8Z

  • PubMed Abstract: 
  • GM1-ganglioside receptor binding by the B subunit of cholera toxin (CtxB) is widely accepted to initiate toxin action by triggering uptake and delivery of the toxin A subunit into cells. More recently, GM1 binding by isolated CtxB, or the related B subunit of Escherichia coli heat-labile enterotoxin (EtxB), has been found to modulate leukocyte function, resulting in the down-regulation of proinflammatory immune responses that cause autoimmune disorders such as rheumatoid arthritis and diabetes ...

    GM1-ganglioside receptor binding by the B subunit of cholera toxin (CtxB) is widely accepted to initiate toxin action by triggering uptake and delivery of the toxin A subunit into cells. More recently, GM1 binding by isolated CtxB, or the related B subunit of Escherichia coli heat-labile enterotoxin (EtxB), has been found to modulate leukocyte function, resulting in the down-regulation of proinflammatory immune responses that cause autoimmune disorders such as rheumatoid arthritis and diabetes. Here, we demonstrate that GM1 binding, contrary to expectation, is not sufficient to initiate toxin action. We report the engineering and crystallographic structure of a mutant cholera toxin, with a His to Ala substitution in the B subunit at position 57. Whereas the mutant retained pentameric stability and high affinity binding to GM1-ganglioside, it had lost its immunomodulatory activity and, when part of the holotoxin complex, exhibited ablated toxicity. The implications of these findings on the mode of action of cholera toxin are discussed.


    Organizational Affiliation

    Department of Pathology and Microbiology, University of Bristol, Bristol BS81TD, United Kingdom.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CHOLERA TOXIN B PROTEINA [auth D],
B [auth E],
C [auth F],
D [auth G],
E [auth H]
103Vibrio choleraeMutation(s): 1 
Gene Names: ctxB
UniProt
Find proteins for P01556 (Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961))
Explore P01556 
Go to UniProtKB:  P01556
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01556
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GAL
Query on GAL

Download Ideal Coordinates CCD File 
F [auth D],
G [auth F],
H [auth G],
I [auth H]
beta-D-galactopyranose
C6 H12 O6
WQZGKKKJIJFFOK-FPRJBGLDSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.179 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 101.362α = 90
b = 114.722β = 90
c = 45.591γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
d*TREKdata reduction
HKL-2000data scaling
AMoREphasing

Structure Validation

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Ligand Structure Quality Assessment 



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-07-25
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Structure summary
  • Version 1.4: 2021-10-27
    Changes: Database references, Structure summary