1S5E

Cholera holotoxin, Crystal form 1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.167 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structures of an intrinsically active cholera toxin mutant yield insight into the toxin activation mechanism

O'Neal, C.J.Amaya, E.I.Jobling, M.G.Holmes, R.K.Hol, W.G.

(2004) Biochemistry 43: 3772-3782

  • DOI: 10.1021/bi0360152
  • Primary Citation of Related Structures:  1S5B, 1S5C, 1S5D, 1S5F

  • PubMed Abstract: 
  • Cholera toxin (CT) is a heterohexameric bacterial protein toxin belonging to a larger family of A/B ADP-ribosylating toxins. Each of these toxins undergoes limited proteolysis and/or disulfide bond reduction to form the enzymatically active toxic fra ...

    Cholera toxin (CT) is a heterohexameric bacterial protein toxin belonging to a larger family of A/B ADP-ribosylating toxins. Each of these toxins undergoes limited proteolysis and/or disulfide bond reduction to form the enzymatically active toxic fragment. Nicking and reduction render both CT and the closely related heat-labile enterotoxin from Escherichia coli (LT) unstable in solution, thus far preventing a full structural understanding of the conformational changes resulting from toxin activation. We present the first structural glimpse of an active CT in structures from three crystal forms of a single-site A-subunit CT variant, Y30S, which requires no activational modifications for full activity. We also redetermined the structure of the wild-type, proenzyme CT from two crystal forms, both of which exhibit (i) better geometry and (ii) a different A2 "tail" conformation than the previously determined structure [Zhang et al. (1995) J. Mol. Biol. 251, 563-573]. Differences between wild-type CT and active CTY30S are observed in A-subunit loop regions that had been previously implicated in activation by analysis of the structure of an LT A-subunit R7K variant [van den Akker et al. (1995) Biochemistry 34, 10996-11004]. The 25-36 activation loop is disordered in CTY30S, while the 47-56 active site loop displays varying degrees of order in the three CTY30S structures, suggesting that disorder in the activation loop predisposes the active site loop to a greater degree of flexibility than that found in unactivated wild-type CT. On the basis of these six new views of the CT holotoxin, we propose a model for how the activational modifications experienced by wild-type CT are communicated to the active site.


    Organizational Affiliation

    Department of Chemistry and Biomolecular Structure Center, University of Washington, Seattle, Washington 98195, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cholera enterotoxin, A chain precursor
A, B
240Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961)Gene Names: ctxA (toxA)
EC: 2.4.2.-
Find proteins for P01555 (Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961))
Go to UniProtKB:  P01555
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
cholera toxin B protein (CTB)
D, E, F, G, H, J, K, L, M, N
103Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961)Gene Names: ctxB (toxB)
Find proteins for P01556 (Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961))
Go to UniProtKB:  P01556
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A, B
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
GAL
Query on GAL

Download SDF File 
Download CCD File 
D, J
BETA-D-GALACTOSE
C6 H12 O6
WQZGKKKJIJFFOK-FPRJBGLDSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.167 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 59.931α = 90.00
b = 108.230β = 95.89
c = 122.976γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
MOLREPphasing
REFMACrefinement
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-04-06
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Refinement description, Version format compliance