Gryaznov S M, Lloyd D H
Lynx Therapeutics, Inc., Foster City, CA 94404.
Nucleic Acids Res. 1993 Dec 25;21(25):5909-15. doi: 10.1093/nar/21.25.5909.
Synthetic oligonucleotides have been proposed as a new rationally designed class of pharmaceuticals with a mechanism of action based upon a Watson-Crick and/or Hoogsteen type of base pairing with RNA or DNA regions of interest. Two series of 3'-cholesterol and/or 5'-cholesterol conjugated oligonucleotides have been synthesized. The primary structure of these compounds was conceived in a way that should allow a hydrophobic interaction to take place upon bringing the cholesteryl moieties into proximity via a hybridization event. In the first group of compounds the cholesteryl group was tethered to the opposite ends of two oligonucleotides, tandemly addressed to the same complementary strand. An increase in the Tm of duplexes up to 13.3 degrees C was observed in comparison to unmodified oligomers. We observed a higher level of mismatch discrimination for the two contiguous oligonucleotide cholesterol conjugates compared to one continuous oligomer of the same length. A second group of compounds was synthesized as 5',3'-bis-cholesterol containing oligomers, capable of forming 'clamp-shaped' triple-stranded complexes, where cholesterol groups were attached to the termini of duplex and triplex forming domains. Stabilization of triplexes by up to 30 degrees C due to inter-cholesteryl interaction was observed. We detected no triplex formation with a mismatched target. These data suggest that significant stabilization of complexes of nucleic acids could be achieved through inter-cholesteryl hydrophobic interaction.
合成寡核苷酸已被提议作为一类新的合理设计的药物，其作用机制基于与感兴趣的RNA或DNA区域的沃森-克里克和/或 hoogsteen 型碱基配对。已经合成了两个系列的3'-胆固醇和/或5'-胆固醇共轭寡核苷酸。这些化合物的一级结构的设计方式应能通过杂交事件使胆固醇部分靠近时发生疏水相互作用。在第一组化合物中，胆固醇基团连接到两个寡核苷酸的相对末端，串联作用于同一条互补链。与未修饰的寡聚物相比，观察到双链体的解链温度（Tm）升高了13.3摄氏度。与相同长度的一个连续寡聚物相比，我们观察到两个连续的寡核苷酸胆固醇共轭物具有更高水平的错配识别能力。第二组化合物被合成为含有5'，3'-双胆固醇的寡聚物，能够形成“钳形”三链复合物，其中胆固醇基团连接到双链体和三链体形成结构域的末端。观察到由于胆固醇间相互作用，三链体的稳定性提高了30摄氏度。我们未检测到与错配靶标形成三链体。这些数据表明，通过胆固醇间的疏水相互作用可以实现核酸复合物的显著稳定。
