Woo J, Meyer R B, Gamper H B
Epoch Pharmaceuticals, Inc., Bothell, WA 98021, USA.
Nucleic Acids Res. 1996 Jul 1;24(13):2470-5. doi: 10.1093/nar/24.13.2470.
Modified oligodeoxyribonucleotides (ODNs) that have unique hybridization properties were designed and synthesized for the first time. These ODNs, called selective binding complementary ODNs (SBC ODNs), are unable to form stable hybrids with each other, yet are able to form stable, sequence specific hybrids with complementary unmodified strands of nucleic acid. To make SBC ODNs, deoxyguanosine (dG) and deoxycytidine (dC) were substituted with deoxyinosine (dI) and 3-(2'-deoxy-beta-D-ribofuranosyl)pyrrolo-[2,3-d]-pyrimidine-2-(3H)-one (dP), respectively. The hybridization properties of several otherwise identical complementary ODNs containing one or both of these nucleoside analogs were studied by both UV monitored thermal denaturation and non-denaturing PAGE. The data showed that while dI and dP did form base pairs with dC and dG, respectively, dI did not form a stable base pair with dP. A self-complementary ODN uniformly substituted with dI and dP acquired single-stranded character and was able to strand invade the end of a duplex DNA better than an unsubstituted ODN. This observation implies that SBC ODNs should effectively hybridize to hairpins present in single-stranded DNA or RNA.
首次设计并合成了具有独特杂交特性的修饰寡脱氧核糖核苷酸（ODN）。这些ODN被称为选择性结合互补ODN（SBC ODN），它们彼此之间无法形成稳定的杂交体，但能够与互补的未修饰核酸链形成稳定的、序列特异性的杂交体。为了制备SBC ODN，分别用脱氧次黄苷（dI）和3-(2'-脱氧-β-D-呋喃核糖基)吡咯并-[2,3-d]-嘧啶-2-(3H)-酮（dP）取代脱氧鸟苷（dG）和脱氧胞苷（dC）。通过紫外监测热变性和非变性聚丙烯酰胺凝胶电泳（PAGE）研究了几种含有这两种核苷类似物之一或两者的其他方面相同的互补ODN的杂交特性。数据表明，虽然dI和dP分别与dC和dG形成碱基对，但dI与dP没有形成稳定的碱基对。一个均匀地被dI和dP取代的自互补ODN具有单链特性，并且比未取代的ODN更能有效地侵入双链DNA的末端。这一观察结果表明，SBC ODN应该能够有效地与单链DNA或RNA中存在的发夹结构杂交。
