3VBZ

Crystal structure of Taipoxin beta subunit isoform 2


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.76 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.184 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural analysis of trimeric phospholipase A(2) neurotoxin from the Australian taipan snake venom.

Cendron, L.Micetic, I.Polverino de Laureto, P.Paoli, M.

(2012) FEBS J 279: 3121-3135

  • DOI: https://doi.org/10.1111/j.1742-4658.2012.08691.x
  • Primary Citation of Related Structures:  
    3VBZ, 3VC0

  • PubMed Abstract: 

    Snake pre-synaptic neurotoxins endowed with phospholipase A(2) activity are potent inducers of paralysis through the specific disruption of the neuromuscular junction pre-synaptic membrane and represent a valuable tool for investigating neuronal degeneration and recovery. They have different structural complexity and a wide range of lethal potency and enzymatic activity, although they share a similar mechanism of action. Although no correlation has been reported between neurotoxicity and enzymatic activity, toxicity increases with structural complexity and phospholipase A(2) oligomers show 10-fold lower LD(50) values compared to their monomeric counterparts. To date, no structural study has been performed on multimeric SPANs with the aim of shedding light on the correlation between structural complexity and neurotoxicity. In the present study, we investigated the structure of taipoxin, a trimeric phospholipase A(2) neurotoxin, as well as that of its subunits, by X-ray crystallography and small angle X-ray scattering analysis. We present the high-resolution structure of two isoforms of the taipoxin β subunit, which show no neurotoxic activity but enhance the activity of the other subunits in the complex. One isoform shows no structural change that could justify the lack of activity. The other displays three point mutations in critical positions for the catalytic activity. Moreover, we designed a model for the quaternary structure of taipoxin under physiological conditions, in which the three subunits are organized into a flat holotoxin with the substrate binding sockets exposed on the same side of the complex, which suggests a role for this interface in the toxin-membrane interaction.


  • Organizational Affiliation

    Department of Biological Chemistry, University of Padova, Italy.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Phospholipase A2 homolog, taipoxin beta chain
A, B
118Oxyuranus scutellatus scutellatusMutation(s): 11 
EC: 3.1.1.4
UniProt
Find proteins for P0CG57 (Oxyuranus scutellatus scutellatus)
Explore P0CG57 
Go to UniProtKB:  P0CG57
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0CG57
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.76 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.184 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52.57α = 90
b = 36.48β = 110.09
c = 65.56γ = 90
Software Package:
Software NamePurpose
MxCuBEdata collection
PHASERphasing
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-07-25
    Type: Initial release
  • Version 1.1: 2012-09-26
    Changes: Database references
  • Version 1.2: 2023-09-13
    Changes: Data collection, Database references, Refinement description