2A7T

Crystal Structure of a novel neurotoxin from Buthus tamalus at 2.2A resolution.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.205 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structure of a highly acidic neurotoxin from scorpion Buthus tamulus at 2.2A resolution reveals novel structural features.

Sharma, M.Ethayathulla, A.S.Jabeen, T.Singh, N.Sarvanan, K.Yadav, S.Sharma, S.Srinivasan, A.Singh, T.P.

(2006) J.Struct.Biol. 155: 52-62

  • DOI: 10.1016/j.jsb.2005.12.005

  • PubMed Abstract: 
  • The crystal structure of a highly acidic neurotoxin from the scorpion Buthus tamulus has been determined at 2.2A resolution. The amino acid sequence determination shows that the polypeptide chain has 64 amino acid residues. The pI measurement gave a ...

    The crystal structure of a highly acidic neurotoxin from the scorpion Buthus tamulus has been determined at 2.2A resolution. The amino acid sequence determination shows that the polypeptide chain has 64 amino acid residues. The pI measurement gave a value of 4.3 which is one of the lowest pI values reported so far for a scorpion toxin. As observed in other alpha-toxins, it contains four disulphide bridges, Cys12-Cys63, Cys16-Cys36, Cys22-Cys46, and Cys26-Cys48. The crystal structure reveals the presence of two crystallographically independent molecules in the asymmetric unit. The conformations of two molecules are identical with an r.m.s. value of 0.3A for their C(alpha) tracings. The overall fold of the toxin is very similar to other scorpion alpha-toxins. It is a betaalphabetabeta protein. The beta-sheet involves residues Glu2-Ile6 (strand beta1), Asp32-Trp39 (strand beta3) and Val45-Val55 (strand beta4). The single alpha-helix formed is by residues Asn19-Asp28 (alpha2). The structure shows a trans peptide bond between residues 9 and 10 in the five-membered reverse turn Asp8-Cys12. This suggests that this toxin belongs to classical alpha-toxin subfamily. The surface features of the present toxin are highly characteristic, the first (A-site) has residues, Phe18, Trp38 and Trp39 that protrude outwardly presumably to interact with its receptor. There is another novel face (N-site) of this neurotoxin that contains several negatively charged residues such as, Glu2, Asp3, Asp32, Glu49 and Asp50 which are clustered in a small region of the toxin structure. On yet another face (P-site) in a triangular arrangement, with respect to the above two faces there are several positively charged residues, Arg58, Lys62 and Arg64 that also protrude outwardly for a potentially potent interaction with other molecules. This toxin with three strong features appears to be one of the most toxic molecules reported so far. In this sense, it may be a new subclass of neurotoxins with the largest number of hot spots.


    Organizational Affiliation

    Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Neurotoxin
A, B
64Hottentotta tamulusMutation(s): 0 
Find proteins for P60277 (Hottentotta tamulus)
Go to UniProtKB:  P60277
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.205 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 50.871α = 90.00
b = 21.001β = 94.45
c = 52.451γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
SCALEPACKdata scaling
AMoREphasing
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-07-19
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance