Monaco R R, Gardiner W C
Department of Chemistry and Biochemistry, University of Texas at Austin 78712.
Biochem Biophys Res Commun. 1993 Oct 29;196(2):975-83. doi: 10.1006/bbrc.1993.2345.
T-jump chemical relaxation experiments with fluorescence detection were carried out on the binding of ethidium cation to calf thymus DNA over the temperature range from 11 to 35 degrees C for ethidium concentrations from 500 nM to 2 microM, DNA concentrations from 7.5 to 60 microM (base pairs), and KCl concentrations from 20 to 500 mM. In contrast to the findings of earlier investigations, no salt or DNA concentration or temperature dependences were seen that would support a mechanism of intercalation directly from solution or from an electrostatically bound exterior site in rapid equilibrium with solution. It is suggested that the rate-determining process of intercalation in vivo involves large scale dynamics of the DNA itself.
采用荧光检测的T跳跃化学弛豫实验，研究了在11至35摄氏度的温度范围内，溴化乙锭阳离子与小牛胸腺DNA的结合情况，其中溴化乙锭浓度为500 nM至2 microM，DNA浓度为7.5至60 microM（碱基对），氯化钾浓度为20至500 mM。与早期研究结果相反，未观察到盐浓度、DNA浓度或温度依赖性，这表明不存在直接从溶液中或从与溶液处于快速平衡的静电结合外部位点进行嵌入的机制。研究表明，体内嵌入的速率决定过程涉及DNA自身的大规模动力学。
