氮杂大环铈（III）配合物与pUC19 DNA的相互作用

摘要

以一种1,4,7,10,13,16,19,22,25,28,31-十一氮杂2,5,8,11,14,17,20,23,26,29,32-十一酰基-环三十三烷的衍生物(CYC)为配体,在溶液中和Ce(Ⅲ, M)离子形成氮杂大环铈配合物(M-CYC)作为仿生催化剂,通过紫外光谱法、荧光光谱法和凝胶电泳法研究了M-CYC配合物与DNA的相互作用.结果表明, M-CYC与小牛胸腺DNA (CT DNA)以嵌插方式相互作用,在pH =8.16的缓冲体系中,其结合常数Kb =2.0×104 L/mol.凝胶电泳结果表明,当自由基捕捉剂存在时, M-CYC可将超螺旋pUC19 DNA切割为缺刻型DNA,其切割方式为水解切割.%A new biomimetic catalyst (M-CYC) is formed from the combination of CYC (a derivative of 1,4,7,10,13,16,19,22,25,28,31-undecaaza-cyclotritriacontane-2,5,8,11,14,17,20,23,26,29,32-undeca acyl) and Ce(III, M) in aqueous solution. The interaction between this complex and DNA was studied using electronic absorption spectroscopy, fluorescence spectroscopy, and gel electrophoresis. The results indicated that M-CYC and calf thymus DNA (pUC19 DNA) interacted via intercalation. The apparent binding constant of the complex with DNA was determined to be 2.0×104 L/mol at pH 8.16. Based on gel electrophoresis analysis, M-CYC was shown to nick the circular plasmid pUC19 DNA in the presence of a free radical scavenger. The nicking of DNA serves as a model of hydrolyzed cleavage.