Urata H, Ueda Y, Suhara H, Nishioka E, Akagi M
Osaka University of Pharmaceutical Sciences, Japan.
Nucleic Acids Symp Ser. 1993(29):69-70.
We have synthesized heterochiral dodecadeoxynucleotides having an unnatural L-nucleotide residue, and have investigated their structures by ultraviolet (UV) absorption, circular dichroism (CD) measurements and nuclear magnetic resonance (NMR) spectroscopy. It was clearly shown that the overall structures of the heterochiral 12-mers are a right-handed B-conformation and the unnatural L-nucleotide residue in the heterochiral 12-mer (L-4) forms stable Watson-Crick type base-pairing with the natural complementary residue. In this double helix (L-4), the unnatural G4 residue has an S-type sugar conformer and a low-anti glycosidic torsion angle. From the properties of an enantiomer, natural nucleotides may possibly form a low-anti left-handed B-form duplex with the aid of certain factors.
我们合成了含有非天然L-核苷酸残基的异手性十二脱氧核苷酸，并通过紫外（UV）吸收、圆二色性（CD）测量和核磁共振（NMR）光谱对其结构进行了研究。结果清楚地表明，异手性12聚体的整体结构为右手B构象，异手性12聚体（L-4）中的非天然L-核苷酸残基与天然互补残基形成稳定的沃森-克里克型碱基配对。在这个双螺旋（L-4）中，非天然G4残基具有S型糖构象和低反式糖苷扭转角。从对映体的性质来看，天然核苷酸可能在某些因素的帮助下形成低反式左手B型双链体。
