研究了一系列钌(Ⅱ)多吡啶配合物对pBR 322 DNA的光断裂作用,并与光谱法和粘度法的研究结果进行了对比.实验结果表明,钌(Ⅱ)多吡啶配合物光断裂DNA的能力不仅与配合物与DNA相互作用的结合模式和结合强度有关,还与配合物自身的电子结构有关;钌(Ⅱ)多吡啶配合物对DNA的光断裂存在立体选择性;其断裂机理是激发态的配合物与溶液中的氧分子发生能量转移生成单线态氧活性氧化物种,将鸟嘌呤碱基氧化而导致DNA断裂.本研究对于遗传工程中的化学核酸酶以及以DNA为靶标的药物设计有重要的意义.
Photoactivated cleavage of pBR 322 DNA by a series of ruthenium(II) polypyridyl complexes has been studied. The experimental results were compared with our previous observations using spectroscopic methods and viscosity measurements. The experimental results suggest that the capacity of ruthenium(II) polypyridyl complex to photocleavage DNA depends on not only the mode and strength of the complex binding to DNA, but also the electron structure of the complex, and that ruthenium(II) polypyridyl complex can photocleavage DNA enantioselectively. The mechanism of DNA cleavage of these complexes was also discussed and proposed as follows: the excited state of Ru(II) polypyridyl complex transfers its energy to the oxygen in solution, producing singlet molecular oxygen as the active oxygen species in the scission reactions, which oxidizes guanine of DNA and leads to cleavage of DNA. These studies are very important to the design of chemical nucleases and DNA-targeting drugs.
Acta Chimica Sinica