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用UV-Vis吸收光谱、荧光光谱、圆二色谱以及核磁共振光谱等手段研究了硫堇(TH)与两个不同序列寡核苷酸的作用。TH与寡核苷酸作用后的吸收光谱和荧光光谱产生了明显的减色红移和荧光猝灭效应。分别计算了TH与[oligo d(GC)]2和[oligo d(AT)]2作用的荧光猝灭常数和结合常数,结果表明TH与GC序列的结合能力比与AT序列更强。通过TH与[oligo d(GC)]2作用后双螺旋链构象变化以及TH质子的1HNMR谱峰明显变宽,进一步说明TH与寡核苷酸结合的序列选择性。
The effects of thionine (TH) on two different oligonucleotides were studied by UV-Vis absorption, fluorescence, circular dichroism and nuclear magnetic resonance spectroscopy. The absorption and fluorescence spectra of TH with oligonucleotide produced obvious subtractive redshift and fluorescence quenching effects. The fluorescence quenching constants and binding constants of TH interacting with [oligo d (GC)] 2 and [oligo d (AT)] 2 were calculated respectively. The results showed that the binding ability of TH to GC was stronger than that of AT. The conformational changes of the double helix and the broadened 1HNMR spectrum of TH proton broadened by the interaction between TH and [oligo d (GC)] 2, which further illustrate the sequence selectivity of TH binding to oligonucleotides.