Delepierre M, Langlois D'Estaintot B, Igolen J, Roques B P
Eur J Biochem. 1986 Dec 15;161(3):571-7. doi: 10.1111/j.1432-1033.1986.tb10480.x.
Exhaustive conformational studies of d(CpG)2 and d(m5CpG)2, two convenient targets for DNA bisintercalating drugs, have been carried out by 1H and 31P NMR in low salt concentration and in the presence of 30% ethanol. Unambiguous 31P assignments of the B for are obtained with low-power heteronuclear decoupling experiments, while 31P assignments in the Z form are obtained by two-dimensional homonuclear chemical exchange experiments. The 31P chemical shifts and 3JH3'P coupling constants studied at various temperatures in methylated and non-methylated tetranucleotides, are interpreted as resulting from conformational differences between the compounds. These features are corroborated by homonuclear proton nuclear Overhauser effect experiments showing the steric role of the 5-methylcytosine in the induction of an alternating B form in d(m5CpG)2.
已通过1H和31P NMR在低盐浓度和30%乙醇存在的条件下，对d(CpG)2和d(m5CpG)2这两种DNA双插入药物的便捷靶点进行了详尽的构象研究。通过低功率异核去耦实验获得了B型的明确31P归属，而通过二维同核化学交换实验获得了Z型的31P归属。在甲基化和非甲基化四核苷酸中于不同温度下研究的31P化学位移和3JH3'P耦合常数，被解释为由化合物之间的构象差异所致。同核质子核Overhauser效应实验证实了这些特征，该实验表明5-甲基胞嘧啶在诱导d(m5CpG)2中交替B型时的空间作用。
