Biphasic transition curve on denaturation of chicken cystatin by guanidinium chloride Evidence for an independently unfolding structural region

FEBS Letters

Björk, Ingemar¹  Pol, Ewa¹ 

[1] Department of Veterinary Medical Chemistry, Swedish University of Agricultural Sciences, Uppsala Biomedical Center, Box 575, S-751 23 Uppsala, Sweden

关键词: Cysteine proteinase inhibitor;    Cystatin;    Protein denaturation;    Stable intermediate;    Circular dichroism;    Fluorescence;   

DOI  :  10.1016/0014-5793(92)80102-M

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Far-ultraviolet circular dichroism and tryptophan fluorescence measurements showed that the reversible unfolding of the cysteine proteinase inhibitor, chicken cystatin, by guanidinium chloride is a two-step process with transition midpoints at ≈3.4 and ≈5.4 M denaturant. The partially unfolded intermediate had both far- and near-ultraviolet circular dichroism and fluorescence emission spectra comparable to those of the native protein. The largely retained tertiary structure suggests that the intermediate represents a species in which a separate region of lower stability has been unfolded, rather than an intermediate of the ‘molten globule’ type. Such a structurally independent region is apparent in the three-dimensional structure of the inhibitor.

【 授权许可】

Unknown