2CB6

Crystal structure of the catalytic domain of the mosquitocidal toxin from Bacillus sphaericus, mutant E195Q


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.227 

Starting Model: experimental
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This is version 1.3 of the entry. See complete history


Literature

Structure of the Mosquitocidal Toxin from Bacillus Sphaericus.

Reinert, D.J.Carpusca, I.Aktories, K.Schulz, G.E.

(2006) J Mol Biol 357: 1226

  • DOI: https://doi.org/10.1016/j.jmb.2006.01.025
  • Primary Citation of Related Structures:  
    2CB4, 2CB6

  • PubMed Abstract: 

    The catalytic domain of a mosquitocidal toxin prolonged by a C-terminal 44 residue linker connecting to four ricin B-like domains was crystallized. Three crystal structures were established at resolutions between 2.5A and 3.0A using multi-wavelength and single-wavelength anomalous X-ray diffraction as well as molecular replacement phasing techniques. The chainfold of the toxin fragment corresponds to those of ADP-ribosylating enzymes. At pH 4.3 the fragment is associated in a C(7)-symmetric heptamer in agreement with an aggregate of similar size observed by size-exclusion chromatography. In two distinct crystal forms, the heptamers formed nearly spherical, D(7)-symmetric tetradecamers. Another crystal form obtained at pH 6.3 contained a recurring C(2)-symmetric tetramer, which, however, was not stable in solution. On the basis of the common chainfold and NAD(+)-binding site of all ADP-ribosyl transferases, the NAD(+)-binding site of the toxin was assigned at a high confidence level. In all three crystal forms the NAD(+) site was occupied by part of the 44 residue linker, explaining the known inhibitory effect of this polypeptide region. The structure showed that the cleavage site for toxin activation is in a highly mobile loop that is exposed in the monomer. Since it contains the inhibitory linker as a crucial part of the association contact, the observed heptamer is inactive. Moreover, the heptamer cannot be activated by proteolysis because the activation loop is at the ring center and not accessible for proteases. Therefore the heptamer, or possibly the tetradecamer, seems to represent an inactive storage form of the toxin.


  • Organizational Affiliation

    Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MOSQUITOCIDAL TOXIN
A, B, C, D, E
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P
291Lysinibacillus sphaericusMutation(s): 1 
UniProt
Find proteins for Q03988 (Lysinibacillus sphaericus)
Explore Q03988 
Go to UniProtKB:  Q03988
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ03988
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.227 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 106.302α = 90
b = 175.802β = 90
c = 335.503γ = 90
Software Package:
Software NamePurpose
TNTrefinement
XDSdata reduction
XSCALEdata scaling
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-02-22
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description