Michel J, Toulmé J J, Vercauteren J, Moreau S
INSERM U-386, Laboratoire de Biophysique Moléculaire, Université de Bordeaux, France.
Nucleic Acids Res. 1996 Mar 15;24(6):1127-35. doi: 10.1093/nar/24.6.1127.
A major limitation in triple-helix formation arises from the weak energy of interaction between the third strand and the double-stranded target. We tried to increase the stacking interaction contribution within the third strand by extending the aromatic domain of thymine. We report here the use of 2,4-quinazolinedione as a substitute for thymine in the canonical TA*T triplet. The synthesis and the characterization of the quinazoline beta nucleoside Q and of its phosphoramidite derivative is described. Triple-helix- forming oligonucleotides incorporating Q have been prepared and their ability to form triplexes has been evaluated by UV-monitored thermal denaturation measurements. The introduction of one or multiple Q residues, either contiguous or remote from each other, slightly destabilized triple-stranded structures, whatever the nucleic acid base composition (pyrimidine or GT) of the third strand.
三链螺旋形成的一个主要限制源于第三条链与双链靶标之间相互作用的能量较弱。我们试图通过扩展胸腺嘧啶的芳香域来增加第三条链内的堆积相互作用贡献。我们在此报告使用2,4-喹唑啉二酮替代经典TA*T三联体中的胸腺嘧啶。描述了喹唑啉β核苷Q及其亚磷酰胺衍生物的合成与表征。制备了掺入Q的三链螺旋形成寡核苷酸，并通过紫外监测热变性测量评估了它们形成三链体的能力。引入一个或多个Q残基，无论它们彼此相邻还是相隔，都会使三链结构略有不稳定，无论第三条链的核酸碱基组成（嘧啶或GT）如何。
