四甲基吡啶卟啉与核酸相互作用的稳态和时间分辨光谱

采用稳态吸收和荧光光谱、圆二色谱和皮秒时间分辨荧光光谱手段, 研究了5,10,15,20-四4-(N-甲基吡啶)]卟啉(TMPyP4)与腺嘌呤(A)、鸟嘌呤(G)、胸腺嘧啶(T)和胞嘧啶(C)等4种碱基, 以及相应的核苷、核苷酸和单链DNA的结合能力和光谱学性质. 研究结果发现, 嘌呤与TMPyP4的结合能力比嘧啶的强. 对于某一碱基系列, 结合能力强弱顺序依次为: 碱基~核苷<核苷酸<单链DNA. 时间分辨荧光谱研究发现, 除鸟嘌呤外, 核酸和TMPyP4复合物的荧光动力学均含有快(1~2 ns)和慢(约10 ns)两个衰减过程, 它们分别是由激基复合体和环境极性对激发态TMPyP4分子的影响所致. 单链DNA能诱导TMPyP4产生诱导圆二色信号, 而单分子(碱基、核苷、核苷酸)则无此功能.

Steady-state and Time-resolved Spectroscopic Studies on the Interaction Between TMPyP4 and Nucleic Acids

Steady-state absorption and fluorescence, circular dichroism and picosecond time-resolved fluorescence spectroscopies were used to investigate the interaction between 5,10,15,20-tetrakis(4-N-methylpyridine)porphyrin (TMPyP4) and nucleic acid molecules, i.e. bases (A, G, T, C), deoxynucleosides (dA, dG, dT, dC), deoxynucleotides (dAMP, dGMP, dTMP, dCMP) and oligonucleotides (dA6, dG6, dT6, dC6). The results show that the interactions between TMPyP4 and the purine species were stronger than that between TMPyP4 and the pyrimidine species. For a certain series of species, such as A, dA, dAMP and dA6, the interaction strength follows the order: base-nucleoside