Frictional resistance to motions of bimane‐labelled spinach calmodulin in response to ligand binding

FEBS Letters

Yuan, Shixing¹  Haug, Alfred¹ 

[1] Department of Microbiology and Pesticide Research Center, Michigan State University, East Lansing, MI 48824, USA

关键词: Calmodulin;    Protein flexibility;    Fluorescence anisotropy;    Fluctuation;   

DOI  :  10.1016/0014-5793(88)81338-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The single cysteinyl residue 26 of spinach calmodulin was labelled with the thiol-specific bimane fluorescence probe. Following application of stoichiometric quantities of Ca²⁺ or aluminum ions to the protein, temperature-dependent fluorescence changes (anisotropy, lifetime) could be monitored via the label. From these data the Y function could be constructed which, as a function of temperature, seems to consist of two linear regions which intersect at the critical temperature, T _c. From the Y function the thermal coefficient, b(T), of the frictional resistance to fluorophore rotation could be determined. b(T) was dependent on the type and stoichiometry of the ligand(s) bound to calmodulin. Changes of the thermal coefficient apparently resulted in part from ligand-triggered structural pertubations transmitted over a considerable distance to calmodulin region I, the site of the fluorophore.

【 授权许可】

Unknown