应用SDSL-EPR技术研究溶液中牛血清白蛋白的运动性及构象变化  

Study on motional and conformational changes of BSA in solution using SDSL-EPR technique

作　　者：王长振[1] 周宇[2] 丛建波[1] 先宏[1] 郭林超[1] 杨俊涛[1] 唐丽[1] 陈鹏[1] 宁静[1] 胡向军[1] 陈章宝[2] 吴可[1] 

机构地区：[1]军事医学科学院放射与辐射医学研究所,北京100850 [2]西南大学药学院,重庆400715

出　　处：《科学通报》2010年第14期1365-1369,共5页Chinese Science Bulletin

基　　金：国家自然科学基金(30750009和30970693);国家科技部创新方法工作专项(2008IM022000)项目资助

摘　　要：应用位置定向自旋标记-电子顺磁共振(SDSL-EPR)技术研究牛血清白蛋白(BSA)的运动性、构象特征及其加入芹菜素(Apigenin)后的变化.采用MTSL对BSA的第34位半胱氨酸(Cys)进行标记;通过EPR检测计算旋转相关时间τc及强弱固定化之比S/W研究运动性的变化;通过功率饱和实验检测该位点的易趋性,研究构象特点及其变化.在BSA溶液中加入Apigenin后,τc及S/W值明显降低,说明其Cys位点运动性变快;易趋性检测结果显示,34位Cys位点位于蛋白质表面,加入Apigenin后,该位点构象发生改变,且微环境由亲水性变为疏水性.实验揭示BSA同Apigenin能够相互结合,且引起BSA自由Cys位点的运动性和构象的改变.To study the motion and conformation of BSA as well as their changes when interacting with apigenin using SDSL-EPR, the free cysteine （Cys） of BSA was site-directed labeled with MTSL and detected with EPR to calculate the parameter τc and S/W. The conformational change was analyzed via the power saturation experiment to calculate the accessibility. When apigenin was added into the BSA solution, the values of τc and SIW were decreased, indicating that the motion at the Cys site increased; meanwhile, the conformation and the microenvironment were simultaneously changed. The free Cys was found to be located on the BSA surface. The results showed that apigenin may interact with BSA, accompanied by the motional and conformational changes of BSA.

关 键 词：位置定向自旋标记 电子顺磁共振 牛血清白蛋白 芹菜素 运动性 构象 

分 类 号：Q51[生物学—生物化学]