Department of Life Science, Tokyo Institution of Technology, 4259 Nagatsuta, Yokohama 226-8501, Japan.
Bioorg Med Chem Lett. 2013 Feb 1;23(3):776-8. doi: 10.1016/j.bmcl.2012.11.079. Epub 2012 Dec 1.
The consecutive arrangement of 2'-deoxy-6-thioguanosines (s(6)Gs) and 4-thiothymidines (s(4)Ts) in antiparallel triplex-forming oligonucleotides (TFOs) considerably stabilized the resulting antiparallel triplexes with high base recognition ability by the strong stacking effects of thiocarbonyl groups. This result was remarkable because chemical modifications of the sugar moieties and nucleobases of antiparallel TFOs generally destabilize triplex structures. Moreover, in comparison with unmodified TFOs, it was found that TFOs containing s(6)Gs and s(4)Ts could selectively bind to the complementary DNA duplex but not to mismatched DNA duplexes or single-stranded RNA.
2'-脱氧-6-硫代鸟嘌呤核苷（s(6)Gs）和 4-硫代胸腺嘧啶核苷（s(4)Ts）在反平行三链形成寡核苷酸（TFOs）中的连续排列极大地稳定了所得反平行三链体，具有通过硫羰基的强堆积效应的高碱基识别能力。这一结果是显著的，因为反平行 TFO 的糖部分和核碱基的化学修饰通常会使三链结构不稳定。此外，与未修饰的 TFO 相比，发现含有 s(6)Gs 和 s(4)Ts 的 TFO 可以选择性地与互补 DNA 双链结合，而不与错配 DNA 双链或单链 RNA 结合。
