3PLC

Crystal structure of Beta-Cardiotoxin, a novel three-finger cardiotoxin from the venom of Ophiophagus hannah


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.41 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.234 
  • R-Value Observed: 0.237 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Identification of a alpha-helical molten globule intermediate and structural characterization of beta-cardiotoxin, an all beta-sheet protein isolated from the venom of Ophiophagus hannah (king cobra).

Roy, A.Qingxiang, S.Alex, C.Rajagopalan, N.Jobichen, C.Sivaraman, J.Kini, R.M.

(2019) Protein Sci 28: 952-963

  • DOI: 10.1002/pro.3605
  • Primary Citation of Related Structures:  
    3PLC

  • PubMed Abstract: 
  • β-Cardiotoxin is a novel member of the snake venom three-finger toxin (3FTX) family. This is the first exogenous protein to antagonize β-adrenergic receptors and thereby causing reduction in heart rates (bradycardia) when administered into animals, unlike the conventional cardiotoxins as reported earlier ...

    β-Cardiotoxin is a novel member of the snake venom three-finger toxin (3FTX) family. This is the first exogenous protein to antagonize β-adrenergic receptors and thereby causing reduction in heart rates (bradycardia) when administered into animals, unlike the conventional cardiotoxins as reported earlier. 3FTXs are stable all β-sheet peptides with 60-80 amino acid residues. Here, we describe the three-dimensional crystal structure of β-cardiotoxin together with the identification of a molten globule intermediate in the unfolding pathway of this protein. In spite of the overall structural similarity of this protein with conventional cardiotoxins, there are notable differences observed at the loop region and in the charge distribution on the surface, which are known to be critical for cytolytic activity of cardiotoxins. The molten globule intermediate state present in the thermal unfolding pathway of β-cardiotoxin was however not observed during the chemical denaturation of the protein. Interestingly, circular dichroism (CD) and NMR studies revealed the presence of α-helical secondary structure in the molten globule intermediate. These results point to substantial conformational plasticity of β-cardiotoxin, which might aid the protein in responding to the sometimes conflicting demands of structure, stability, and function during its biological lifetime.


    Organizational Affiliation

    Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Beta-cardiotoxin OH-27A, B, C63Ophiophagus hannahMutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for Q69CK0 (Ophiophagus hannah)
Explore Q69CK0 
Go to UniProtKB:  Q69CK0
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.41 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.234 
  • R-Value Observed: 0.237 
  • Space Group: P 31
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 58.949α = 90
b = 58.949β = 90
c = 53.026γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
MOLREPphasing
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-11-16
    Type: Initial release
  • Version 1.1: 2017-10-04
    Changes: Data collection, Refinement description
  • Version 1.2: 2021-03-31
    Changes: Database references