Base-Pairing, Tautomerism, and Mismatch Discrimination of 7-Halogenated 7-Deaza-2‘-deoxyisoguanosine: Oligonucleotide Duplexes with Parallel and Antiparallel Chain Orientation
作者:Frank Seela、Xiaohua Peng、Hong Li
DOI:10.1021/ja0425785
日期:2005.6.1
Oligonucleotides containing 2'-deoxyisoguanosine (1, iG(d)), 7-deaza-2'-deoxyisoguanosine (2, c(7)iG(d)), and its 7-halogenated derivatives 3 and 4 were synthesized on solid phase using the phosphoramidite building blocks 5-7. The hybridization properties of oligonucleotides were studied on duplexes with parallel and antiparallel chain orientation. It was found that the 7-halogenated nucleoside analogues
在固相上合成含有 2'-脱氧异鸟苷 (1, iG(d))、7-deaza-2'-deoxyisoguanosine (2, c(7)iG(d)) 及其 7-卤代衍生物 3 和 4 的寡核苷酸使用亚磷酰胺积木 5-7。在具有平行和反平行链方向的双链体上研究了寡核苷酸的杂交特性。发现 7-卤代核苷类似物 3 和 4 显着增强了平行 (ps) 和反平行 (aps) DNA 中的双链体稳定性。此外,卤化核苷将互变异构酮-烯醇平衡强烈地转向酮形式,K(TAUT) [酮]/[烯醇] 大约 10(4) 接近 2'-脱氧鸟苷 (10(4)- 10(5)),而非卤化的 7-deaza-2' -脱氧异鸟苷 2 的 K(TAUT) 约为 2000,1 的烯醇浓度在水溶液中为 10%。因此,在反平行和平行 DNA 中,核苷 3 和 4 对 dT 的错配辨别能力比化合物 1 或 2 好得多。与 1 或 2 相比,预期