Circular dichroism study of the unfolding-refolding of a cardiotoxin from Taiwan cobra (Naja naja atra) venom

Circular dichroism spectroscopy has been used to study the unfolding-refolding process of a cardiotoxin from Taiwan cobra (Naja naja atra) venom upon addition of fluoroalcohols or sodium dodecyl sulfate (SDS) to its aqueous solution. In these experiments, the disulfide bridges remained intact. The u...

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Bibliographic Details
Published in:Biochemistry (Easton) 1985-09, Vol.24 (20), p.5678-5685
Main Authors: Galat, Andrzej, Yang, Chenchung, Blout, Elkan R
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Biological and medical sciences
Circular Dichroism
Cobra Cardiotoxin Proteins - metabolism
Conformational dynamics in molecular biology
Disulfides - analysis
Elapid Venoms - metabolism
Fundamental and applied biological sciences. Psychology
Models, Molecular
Molecular biophysics
Protein Conformation
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Summary:Circular dichroism spectroscopy has been used to study the unfolding-refolding process of a cardiotoxin from Taiwan cobra (Naja naja atra) venom upon addition of fluoroalcohols or sodium dodecyl sulfate (SDS) to its aqueous solution. In these experiments, the disulfide bridges remained intact. The unfolding process has been found to be reversible both for fluoroalcohols and for SDS unfolding. The reversibility of the unfolding-refolding process of cardiotoxin in aqueous mixtures of fluoroalcohols was dependent on the volume per volume ratio of alcohol to water. SDS did not unfold the secondary structures of cardiotoxin whereas its tertiary structure was affected. If the SDS concentration in aqueous solution exceeded the critical micelle concentration value of SDS, a quasi-refolded state of cardiotoxin was observed. The mechanism of unfolding-refolding is discussed in terms of molecular interactions which might govern the protein conformation in solution.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi00341a059