Sinclair A, Alkema D, Bell R A, Coddington J M, Hughes D W, Neilson T, Romaniuk P J
Biochemistry. 1984 Jun 5;23(12):2656-62. doi: 10.1021/bi00307a018.
Proton NMR was used to study the secondary structure and melting behavior of six self-complementary oligoribonucleotide tetramers, each containing two guanosine and two cytidine residues (GGCC, CCGG, GCCG, CGGC, GCGC, and CGCG). GGCC and CCGG formed perfect duplexes containing four G.C base pairs with Tms of 54 and 47.8 degrees C, respectively; GCCG and CGGC formed staggered duplexes with two G.C base pairs and four 3' double-dangling bases, with Tms of 35.5 and 29.2 degrees C, respectively; GCGC formed a perfect duplex with a Tm of 49.9 degrees C, while CGCG formed a staggered duplex with a Tm of 36.9 degrees C. From these results, an order of stability of the cores containing two G.C base pairs was proposed: GC:GC is more stable than GG:CC which is more stable than CG:CG. The RY model for secondary structure stability prediction was applied to the above tetramers with reasonable success. Suggestions for refinements are discussed.
质子核磁共振被用于研究六个自我互补的寡核糖核苷酸四聚体的二级结构和熔解行为，每个四聚体都含有两个鸟苷和两个胞苷残基（GGCC、CCGG、GCCG、CGGC、GCGC和CGCG）。GGCC和CCGG形成了含有四个G.C碱基对的完美双链体，其熔解温度分别为54和47.8摄氏度；GCCG和CGGC形成了具有两个G.C碱基对和四个3'端双悬垂碱基的交错双链体，其熔解温度分别为35.5和29.2摄氏度；GCGC形成了一个熔解温度为49.9摄氏度的完美双链体，而CGCG形成了一个熔解温度为36.9摄氏度的交错双链体。根据这些结果，提出了含有两个G.C碱基对的核心稳定性顺序：GC:GC比GG:CC更稳定，而GG:CC比CG:CG更稳定。二级结构稳定性预测的RY模型应用于上述四聚体，取得了合理的成功。文中还讨论了改进的建议。
