摘要
本文报导以Tb^(3+)作为荧光探针,研究钙调蛋白(CaM)与其拮抗药物分子间相互作用的机制.所用方法简便、快速、灵敏.CaM的内源荧光研究表明,Tb^(3+)类似于Ca^(2+),也能诱导CaM分子构象发生改化,由于CaM分子中Ca^(2+)的第Ⅲ、Ⅳ结合位点上各有一个Tyr线基,如(?)280nm激发,则发生从Tyr向Tb^(3+)的能量转移,从而导致Tb^(3+)在490和545nm处的特征荧光发射大大加强.本文检测了药物分子与Tb^(3+)-CaM结合对该荧光发射的影响.实验表明,TFP与CaM的高亲和位点处于CaM分子C-末端部位,即含第Ⅲ、Ⅳ结构域的半分子上:丙拮抗药物酸枣仁皂甙A则优先结合在含第Ⅰ、Ⅱ的结构域的另一半分子(?).
A simple, rapid and sensitive method determining the binding sites of antagonists on calmodulin was introduced.Studies on the intrinsic fluorescence of calmodulin have shown that Tb3+ can efficiently bind to the Ca2+ -binding sites on calmodulin and then induce conformational changes similar to those of Ca2+. Because each of domains III and IV on calmodulin has one tyrosine, the binding of Tb3+ to calmodulin was followed by obvious increase of Tb3+ fluo-rescence at 490 nm and 545nm, which was caused by exciting the calmodulin tyrosine at 280 nm with energy transfer from tyrosine to Tb3+ . By studing the effect of calmodulin antagonists on this fluorescence, it was found that the binding sites of TEP were located on the C-terminal part of calmodulin which contains the domains III and IV; whereas the binding sites of jujuboside A were located on the N-terminal part which contains the domains I and II.
出处
《生物物理学报》
CAS
CSCD
北大核心
1990年第3期300-305,共6页
Acta Biophysica Sinica
基金
国家自然科学基金资助项目