Madsen Andreas S, Hrdlicka Patrick J, Kumar T Santhosh, Wengel Jesper
Nucleic Acid Center, Department of Chemistry, University of Southern Denmark, DK-5230 Odense M, Denmark.
Carbohydr Res. 2006 Jul 24;341(10):1398-407. doi: 10.1016/j.carres.2006.04.010. Epub 2006 May 18.
Nucleotides with conformationally restricted carbohydrate rings such as locked nucleic acid (LNA), alpha-L-LNA or 2',5'-linked 3'-O,4'-C-methyleribonucleotides exhibit significant potential as building blocks for antigene and antisense strategies. 2',5'-Linked alpha-L-ribo configured monomer X (termed alpha-L-ONA) was designed as a potential structural mimic of alpha-L-LNA. The corresponding phosphoramidite building block of monomer X was obtained in five steps (10% overall yield) from the easily obtainable thymine derivative 1. Incorporation of monomer X into oligodeoxyribonucleotides (ONs) results in dramatically decreased thermal stabilities with DNA/RNA complements (DeltaTm/mod=-11.5 to -17.0 degrees C) compared to unmodified reference ONs. Less pronounced decreases (DeltaTm/mod=-4.5 to -8.5 degrees C) are observed when monomer X is incorporated into triplex forming ONs and targeted against double-stranded DNA (parallel orientation, pyrimidine motif). This biophysical data, together with modelling studies, suggest that 2',5'-linked alpha-L-ONA is a poor structural mimic of alpha-L-LNA.
具有构象受限碳水化合物环的核苷酸，如锁核酸（LNA）、α-L-LNA或2',5'-连接的3'-O,4'-C-甲基核糖核苷酸，作为反基因和反义策略的构建模块具有显著潜力。2',5'-连接的α-L-核糖构型单体X（称为α-L-ONA）被设计为α-L-LNA的潜在结构模拟物。单体X相应的亚磷酰胺构建模块由易于获得的胸腺嘧啶衍生物1经五步反应制得（总产率10%）。与未修饰的参考寡脱氧核糖核苷酸（ONs）相比，将单体X掺入寡脱氧核糖核苷酸（ONs）中会导致与DNA/RNA互补物的热稳定性显著降低（ΔTm/mod = -11.5至-17.0℃）。当单体X掺入形成三链体的ONs并靶向双链DNA（平行取向，嘧啶基序）时，观察到的降低不太明显（ΔTm/mod = -4.5至-8.5℃）。这些生物物理数据以及建模研究表明，2',5'-连接的α-L-ONA是α-L-LNA较差的结构模拟物。
