The preparation and characterisation of cyclam/anthraquinone macrocyle/intercalator complexes and their interactions with DNA
作者:Leanne T. Ellis、David F. Perkins、Peter Turner、Trevor W. Hambley
DOI:10.1039/b302123h
日期:——
A new series of macrocycle/intercalator adducts have been prepared from cyclam (1,4,8,11-tetraazacyclotetradecane) and the 1- and 2-substituted anthraquinones (1-[(2-aminoethyl)amino]anthracene-9,10-dione (1C2mac), 1-[(3-aminopropyl)amino]anthracene-9,10-dione (1C3mac), 2-[(3-aminopropyl)amino]anthracene-9,10-dione (2C3mac)). The copper complexes of two of these adducts were prepared and the crystal structure of the complex of 1C2mac ([Cu(1C2mac)(CH3CN)2](PF6)2.0.2H2O) was determined as the hexafluorophosphate salt. The equilibrium constants for the binding to DNA of 1C2-mac, with and without the copper added, were found by UV titrations to be 4.7 × 103 M−1 and 6.2 × 103 M−1, respectively. Reaction with plasmid DNA allowed comparison between the effects of the cyclam/anthraquinone adducts, their copper complexes and the intercalators alone. Addition of the macrocycle increased the extent and effect of DNA intercalation and addition of copper increased the effect still further. The adducts with the longer side chains caused substantially more unwinding of the DNA. None of the adducts inhibited cleavage at dGpG or dGpC sites by restriction enzymes. Molecular modelling was used to investigate the effects of the side chain for a number of possible DNA binding modes. These models reveal that intercalation is not significantly interfered with by the presence of the macrocycle, irrespective of the position of attachment. The increased unwinding caused by adducts with the longer side chain is therefore most likely to be due to specific interactions between the macrocycle and the DNA.
一系列新的宏环/插层剂加合物是由环四氮烷(1,4,8,11-四氮杂环十四烷)和1-、2-取代的蒽醌(1-[(2-氨乙基)氨基]蒽醌-9,10-二酮(1C2mac)、1-[(3-氨丙基)氨基]蒽醌-9,10-二酮(1C3mac)、2-[(3-氨丙基)氨基]蒽醌-9,10-二酮(2C3mac))制备的。两种这些加合物的铜复合物已被制备,并且1C2mac的复合物([Cu(1C2mac)(CH3CN)2](PF6)2·0.2H2O)的晶体结构被确定为六氟磷酸盐。通过UV滴定法,发现1C2mac与DNA结合的平衡常数分别为4.7 × 10³ M−1(未添加铜)和6.2 × 10³ M−1(添加铜)。与质粒DNA反应使得可以比较宏环/蒽醌加合物、它们的铜复合物以及单独插层剂的影响。添加宏环增加了DNA插层的程度和影响,而添加铜则进一步增强了效果。具有较长侧链的加合物导致DNA的解旋显著增加。没有任何加合物抑制限制酶在dGpG或dGpC位点的切割。分子模拟用于研究侧链对多种可能DNA结合模式的影响。这些模型显示,无论附着位置如何,宏环的存在并不明显干扰插层。因此,侧链较长的加合物所引起的增加的解旋最可能是由于宏环与DNA之间的特定相互作用。