Acta Scientiarum Naturalium Universitatis Pekinensis

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FT IR Study on the Secondary Structure of Earthworm Calmodulin(CaM) and the Effects of Ca2+ and Tb3+ Ions

WANG Libo1, WU Jinguang1, XU Guangxian1, WANG Caiqing2, ZHANG Tingfang2   

  1. 1College of Chemistry and Molecular Engineering, Peking University, State Key Labortory of Rare Earth Material Chemistry and Application, Beijing, 100871; 2College of Life Sciences, Peking University, Beijing, 100871
  • Received:1997-06-26 Online:1997-11-20 Published:1997-11-20


王立波1, 吴瑾光1, 徐光宪1, 王采芹2, 张庭芳2   

  1. 1北京大学化学与分子工程学院,稀土材料化学及应用国家重点实验室,北京,100871; 2北京大学生命科学学院,北京,100871

Abstract: The Secondary structure of earthworm Calmodulin(CaM) in thin film was measured by using FT-IR spectroscopic method and curve fitting technique, and the effects of Ca2+ and Tb3+ were investigated in detail. The results show that CaM exhibits lower content of α-helix and relatively higher contents of β-sheet and beta-turn structure in film than that in crystal or water solution. To some extent, the addition of different ratios of Ca2+ and Tb3+ induced different conformation changes, which indicates that the two ions have different combination mechanisms. Moreover, the activity to stimulate the PDE enzyme and the SDS-PAGE behavior of CaM with different metal ions were also studied. The results show that Tb3+ can active CaM under low concentration, but inhibit the activity of CaM under high concentration, which suggests that Tb3+ have different physiology role from Ca2+.

Key words: FTIR, CaM, secondary structure, Ca2+, Tb3+

摘要: 运用FT-IR方法的分辨率增强及曲线拟合技术对水化膜中蚯蚓钙调素CaM的二级结构以及加入不同比例Ca2+、Tb3+后CaM二级结构的变化进行了研究。结果表明,水化膜中CaM及含不同比例Ca2+或Tb3+的蛋白复合物的α-helix的含量较晶体和溶液中为低,而β-sheet和turn结构的含量相对较高。研究发现不同比例金属离子的加入,引起了CaM二级结构不同程度的变化,但各类结构在总量上观察不到明显的变化规律,且由于结合机制的不同,Ca2+和Tb3+的影响也各不相同。Tb3+可与CaM中的Ca结合位点结合,在一定条件下激活CaM,但在较高浓度下,Tb3+的结合抑制CaM的活性。

关键词: FTIR, CaM, 二级结构, Ca2+, Tb3+

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