八肋游仆虫中心蛋白N-端半分子金属离子结合性质的光谱研究

摘要

Ca~(2+) binding is essential for the biological functions of centrins as a trigger/sensor protein to reg-ulate many biological processes in the Ca~(2+)-signaling cascade. In this paper,the metal binding characteristic and conformational change of N-terminal domain of Ciliate Euplotes Octocarinatus centrin (P_(12)) with dif-ferent lanthanide metal ions and the force acting between P_(12) and Tb~(2+) were investigated using TNS and Tb~(3+) as fluorescence probe. The results showed that the hydrophobic surface which was exposed by Ln~(3+)binding was proportional to the potential of lanthanide ions and that the two metal ions binding sites of N-terminal domain (P_(12)) of centrin was occupied by lanthanide ions through electrostatic force under the con-dition of pH 7.4,0.01 mol/L Hepes.%Ca~(2+)在中心蛋白调节许多生理过程并发挥生物功能中起到很重要的作用.本文分别使用TNS、Tb~(3+)为荧光探针研究了八肋游仆虫中心蛋白N-端半分子(P_(12))与不同稀土离子的结合性质及对其构象变化的影响和P_(12)与Tb~(3+)结合的热力学性质.结果表明,在pH 7.4、0.01 mol/L Hepes条件下,中心蛋白与稀土离子结合的稳定性和稀土离子饱和的蛋白质疏水区暴露程度与稀土离子静电势成正比;稀土离子主要以静电作用占据八肋游仆虫中心蛋白N-端区域的金属离子结合部位.