金属离子和变性条件对野花生豆凝集素活性和构象的影响  

The Effects of Metal Ions and Denaturants on the Conformation and Hemagglutinating Activity of Crotalaria mucronata lectin

作　　者：赵曦[1] 荣艳珍[1] 常丽青[1] 高顺[1] 吴传芳[1] 李宜瑾[1] 王陈继[1] 鲍锦库[1] 

机构地区：[1]四川大学生命科学学院,成都610064

出　　处：《四川大学学报（自然科学版）》2005年第1期179-184,共6页Journal of Sichuan University(Natural Science Edition)

基　　金：国家自然科学基金(39770178)

摘　　要：野花生豆凝集素在pH7.0和pH5.0缓冲体系中,用EDTA去除其金属离子,CML凝血活性下降.Ca2+、Mg2+、Mn2+、Zn2+可使去除金属离子CML活性基本恢复到天然水平,表明这些二价金属离子为CML活性所必需.研究不同温度和不同浓度盐酸胍条件下CML的圆二色谱、荧光光谱及其凝血活性的变化,结果表明CML含有较多β 折叠,具有较强的抗变性能力;脲变性的时间扫描荧光光谱证实了CML变性过程的阶段性.To elucidate the relationship between conformational change and hemagglutinating activity of Crotalaria mucronata lectin (CML), the effects of metal ions and denaturants on conformation and hemagglutination of CML were studied. The agglutinating activity of CML decreased obviously after removing metal ions from CML. Incubation of the deionized CML with Ca^(2+), Mg^(2+), Mn^(2+), Zn^(2+ )respectively, recovered the agglutinating activity of CML to its natural level. It showed that some ions were helpful to stabilize the conformation of CML. Circular dichroism (CD) spectrum of natural CML indicated that β-sheets dominated in its secondary structure. The change of CD spectrum and hemagglutination of CML at different pH, temperature and guanidinium hydrochloride concentration indicated that CML had a comparably stable structure despite of containing high β-sheet and lack of disulfide bond. The denaturation was a two-step process. First, CML didn't lose activity despite of its structural changes because these changes were out of the activity center. Second, the activity center was destroyed and CML lost its agglutinating activity completely. And the fluorescence spectra (FLS) of CML at different temperature also revealed that there were two steps during the denaturation.

关 键 词：野花生豆凝集素 金属离子 圆二色谱 荧光光谱 生物学活性 

分 类 号：Q68[生物学—生物物理学]