稀土离子对钙调蛋白与单克隆抗体分子识别的影响

Influence of Rare Earth Irons on the Molecular Recognition Between Calmodulin and Monoclonal Antibody

分别采用酶联免疫吸附 (ELISA)法和荧光标记技术比较了 Ca2 +,La3 +,Eu3 +和 Yb3 +离子对钙调蛋白与单克隆抗体 2 C3之间分子识别的影响 .结果表明 ,金属离子与钙调蛋白作用后会诱导其发生不同的构象变化 ,并进一步影响到钙调蛋白与单克隆抗体 2 C3分子之间的结合强度 .当钙调蛋白分别与 La3 +,Eu3 +,Yb3 +作用后 ,它与单抗 2 C3分子之间的解离常数为 (2 6 .8± 2 .5 ) ,(2 1 .8± 3.4 )和 (6 4 .8± 5 .1 ) nmol/ L,而结合 Ca2 +前后的钙调蛋白与单抗分子的解离常数分别为 (1 77.2± 2 .8)和 (1 5 7± 4 .2 ) nmol/ L.这一结果表明 ,稀土离子诱导钙调蛋白发生的构象变化明显不同于钙离子的作用 ,这种差异可能是稀土与钙离子对钙调蛋白调控作用表现出差别的原因 .

The molecular recognitions between monoclonal antibody 2C3 and calmodulin saturated with different metal ions(La 3+, Eu 3+, Yb 3+ and Ca 2+) were investigated by the enzyme linked immunosorbent assay(ELISA) and labeled fluorescence spectroscopy. The results indicate that after binding with different metal ions, the calmodulin undergoes different conformational changes, which have a significant effect on its recognition ability to a metal ion induced conformation-specific monoclonal antibody. The dissociation constants between the antibody and the calmodulin saturated with La 3+, Eu 3+, Yb 3+ are (26.8±2.5), (21.8±3.4) and (64.8±5.1) nmol/L, respectively, while the dissociation constants between the antibody and Ca 2+-CaM or apoCaM are (157±4.2) and (177.2±2.8) nmol/L, respectively. This result indicates lanthanide-induced conformational changes of calmodulin are not similar with that induced by calcium, which maybe account for the facts that lanthanide and calcium ions lead to different effects on the regulating function of calmodulin in biological systems.