Zhao Ping, Xu Lian-Cai, Huang Jin-Wang, Zheng Kang-Cheng, Fu Bo, Yu Han-Cheng, Ji Liang-Nian
MOE Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, PR China.
Biophys Chem. 2008 Jun;135(1-3):102-9. doi: 10.1016/j.bpc.2008.03.013. Epub 2008 Apr 7.
Four tricationic pyridium porphyrins appending hydroxyphenyl, methoxyphenyl, propionoxyphenyl or carboxyphenyl group at meso-20-position of porphyrin core have been synthesized and their abilities to bind and cleave DNA have been investigated. Using a combination of absorption, fluorescence, circular dichroism (CD) spectra, thermal DNA denaturation as well as viscosity measurements, their binding modes and intrinsic binding constants (K(b)) to calf DNA (CT DNA) were comparatively studied and also compared with those of 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP). The results suggest that the K(b) values of these porphyrins are greatly influenced by the number of positive charges and steric hindrance. Theoretical calculations applying the density functional theory (DFT) have been carried out and explain their DNA-binding properties reasonably. The efficiency of DNA photocleavage by these porphyrins shows high dependence on the values of K(b).
合成了四种在卟啉核的中位-20位连接有羟苯基、甲氧基苯基、丙酰氧基苯基或羧苯基的三阳离子吡啶卟啉，并研究了它们结合和切割DNA的能力。结合吸收光谱、荧光光谱、圆二色光谱（CD）、热DNA变性以及粘度测量，对它们与小牛DNA（CT DNA）的结合模式和固有结合常数（K(b)）进行了比较研究，并与5,10,15,20-四（1-甲基吡啶-4-基）卟啉（TMPyP）的结合模式和固有结合常数进行了比较。结果表明，这些卟啉的K(b)值受正电荷数量和空间位阻的影响很大。应用密度泛函理论（DFT）进行了理论计算，合理地解释了它们的DNA结合特性。这些卟啉对DNA的光切割效率高度依赖于K(b)值。
