Ni(Ⅱ)-EDTA配合物与DNA相互作用机制的光谱学研究

Mechanism of Interaction Between Ni(Ⅱ)-EDTA Complex and DNA by Spectroscopy

应用光谱学方法以吖啶橙(AO)作探针研究了Ni(Ⅱ)-EDTA与DNA的作用机制.研究表明,Ni(Ⅱ)与EDTA形成配离子的摩尔结合比nNi(Ⅱ)∶nEDTA=1∶1,配合物Ni(Ⅱ)-EDTA与DNA的摩尔结合比为nNi(Ⅱ)-EDTA∶nDNA=2∶1,其结合常数K■B25℃=2.77×105 L.mol-1,K■B37℃=2.01×105 L.mol-1.该过程为熵和焓共同驱动,其ΔrS■m=171.39J.(mol.K)-1,ΔrH■m=-2.05×104 J.mol-1,25℃时ΔrG■m=-3.06×104 J.mol-1.Scatchard法和探针法等均表明Ni(Ⅱ)-EDTA与DNA之间的结合方式以沟区作用为主.

The mechanism of Interaction of Ni（ Ⅲ）-EDTA with DNA was studied by using acridine orange（AO） as a probe, which has been confirmed by spectroscopy method. The results indicate that there is a complex of Ni and EDTA. The binary complex ratio of nNi（Ⅱ） rDTA nDNA is 2 1, in which nN（Ⅱ） nrDTA is 1 ： 1. The binding constant of Ni （ Ⅱ ）-EDTA with herring sperm DNA： IxB25 = 2.77 X× 102 L·mol-1,KB37c = 2.01 X× 10^5 Lo molt. The process is driven collectively by entropy and enthalpy, and its ArSm =171.39 J.（mol.K） 1 ,ArHm =--2.05×104 J.mo1-1. At 25℃, ArGm- 3.06 × 10^4 J · mol-1. Scatehard plots and probe method show that the mode of the binding of Ni（ Ⅱ ）-EDTA to DNA is mainly a groove action.