ISSN:
1432-1432
Keywords:
Scorption toxins
;
Molecular modelling
;
X-ray crystallography
;
Protein evolution
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The three-dimensional structure of the insect-directed toxin from the scorpionAndroctonus australis Hector has been modelled using computer graphics and energy-minimization techniques. The model-building procedure was based on the known high resolution structures of two scorption toxins of different types: toxin II fromA. australis Hector, an α-toxin, and variant 3 fromCentruroides sculpturatus Ewing that belongs to the β-toxin structural group. Although the insect-directed toxin has one atypical disulfide bridge, the general structural features of the scorption toxin family, including the presence of a “conserved-hydrophobic” surface, seem to be well-conserved. However, the orientation and length of some loops and regions thought to be important for toxicity are different for α-toxins, β-toxins, and the insect-directed toxin. Thus, the binding of a scorpion toxin to its site on the Na+ channel seems to be based on (1) the presence of a surface containing a series of conserved and/or hydrophobic residues, more or less common to all these molecules, and (2) an adjacent area that modulates the specificity of the interaction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02106182
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