1LT4

HEAT-LABILE ENTEROTOXIN MUTANT S63K


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.192 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structure of a non-toxic mutant of heat-labile enterotoxin, which is a potent mucosal adjuvant.

van den Akker, F.Pizza, M.Rappuoli, R.Hol, W.G.

(1997) Protein Sci. 6: 2650-2654

  • DOI: 10.1002/pro.5560061220

  • PubMed Abstract: 
  • Two closely related bacterial toxins, heat-labile enterotoxin (LT-I) and cholera toxin (CT), not only invoke a toxic activity that affects many victims worldwide but also contain a beneficial mucosal adjuvant activity that significantly enhances the ...

    Two closely related bacterial toxins, heat-labile enterotoxin (LT-I) and cholera toxin (CT), not only invoke a toxic activity that affects many victims worldwide but also contain a beneficial mucosal adjuvant activity that significantly enhances the potency of vaccines in general. For the purpose of vaccine design it is most interesting that the undesirable toxic activity of these toxins can be eliminated by the single-site mutation Ser63Lys in the A subunit while the mucosal adjuvant activity is still present. The crystal structure of the Ser63Lys mutant of LT-I is determined at 2.0 A resolution. Its structure appears to be essentially the same as the wild-type LT-I structure. The substitution Ser63Lys was designed, based on the wild-type LT-I crystal structure, to decrease toxicity by interfering with NAD binding and/or catalysis. In the mutant crystal structure, the newly introduced lysine side chain is indeed positioned such that it could potentially obstruct the productive binding mode of the substrate NAD while at the same time its positive charge could possibly interfere with the critical function of nearby charged groups in the active site of LT-I. The fact that the Ser63Lys mutant of LT-I does not disrupt the wild-type LT-I structure makes the non-toxic mutant potentially suitable, from a structural point of view, to be used as a vaccine to prevent enterotoxigenic E. coli infections. The structural similarity of mutant and wild-type toxin might also be the reason why the inactive Ser63Lys variant retains its adjuvant activity.


    Related Citations: 
    • Crystal Structure of a Cholera Toxin-Related Heat-Labile Enterotoxin from E. Coli
      Sixma, T.K.,Pronk, S.E.,Kalk, K.H.,Wartna, E.S.,Van Zanten, B.A.,Witholt, B.,Hol, W.G.
      (1991) Nature 351: 371
    • Refined Structure of Escherichia Coli Heat-Labile Enterotoxin, a Close Relative of Cholera Toxin
      Sixma, T.K.,Kalk, K.H.,Van Zanten, B.A.,Dauter, Z.,Kingma, J.,Witholt, B.,Hol, W.G.
      (1993) J.Mol.Biol. 230: 890
    • Probing the Structure-Activity Relationship of Escherichia Coli Lt-A by Site-Directed Mutagenesis
      Pizza, M.,Domenighini, M.,Hol, W.,Giannelli, V.,Fontana, M.R.,Giuliani, M.M.,Magagnoli, C.,Peppoloni, S.,Manetti, R.,Rappuoli, R.
      (1994) Mol.Microbiol. 14: 51


    Organizational Affiliation

    Department of Biochemistry, University of Washington, Seattle 98195-7420, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
HEAT-LABILE ENTEROTOXIN
D, E, F, G, H
103Escherichia coliGene Names: eltB (ltpB)
Find proteins for P32890 (Escherichia coli)
Go to UniProtKB:  P32890
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
HEAT-LABILE ENTEROTOXIN
A
247Escherichia coliGene Names: lt-A (K63)
Find proteins for Q2HQJ7 (Escherichia coli)
Go to UniProtKB:  Q2HQJ7
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
BGC
Query on BGC

Download SDF File 
Download CCD File 
D, E, F, G, H
BETA-D-GLUCOSE
C6 H12 O6
WQZGKKKJIJFFOK-VFUOTHLCSA-N
 Ligand Interaction
GAL
Query on GAL

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.192 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 120.000α = 90.00
b = 101.900β = 90.00
c = 64.400γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
X-PLORrefinement
DENZOdata reduction
X-PLORmodel building
X-PLORphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1997-06-16
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance