壳聚糖季铵盐对小牛胸腺DNA的作用研究
Study on the interaction between quaternary ammonium salt of chitosan and calf thymus DNA
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摘要: 本文采用均相法合成了水溶性壳聚糖季铵盐（HTCC）,利用傅里叶红外（FTIR）光谱及核磁共振氢谱（1H NMR）对其结构进行了表征,结果表明,HTCC为壳聚糖C2位氨基H被季铵盐侧链取代的产物。在p H7.4的生理条件下,以吖啶橙（AO）为荧光探针,采用荧光光谱法、圆二色谱法,并结合小牛胸腺DNA（ct DNA）热变性测定等实验手段,初步探讨了HTCC与ct DNA的相互作用机理,荧光光谱的分析结果表明:HTCC对AO-ct DNA体系有猝灭作用,且符合静态猝灭特征。圆二色谱、热变性曲线分析结果表明:HTCC主要以嵌插的方式与ct DNA结合,使双螺旋结构更紧密。Abstract: 2-Hydroxypropyltrimethyl ammonium chloride chitosan( HTCC) were synthesed in heterogeneous system and characterized by IR and NMR spectroscopy. HTCC was the product that the N-H of CS located at C2 was replaced by quaternary ammonium salt. In the physiplogical environment( p H = 7.4). The interaction of HTCC with calf thytus DNA( ct DNA) were performed by fluorescence spectra and circular dichroism spectra,using acridine orange( AO) as a molecular probe.The analysis of UV Vis and fluorescence spectra showed that there was strong interaction between HTCC and ct DNA,the addition of HTCC made the fluorescence quenched effectively,which fitted the characteristics of the static fluorescence quenching. The circular dichroism spectra and thermal denaturation experiment proved that they combined with each other through the intercalative binding mode.
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