Rohozinski J, Hancock J M, Keniry M A
Research School of Biological Sciences, Australian National University, Canberra.
Nucleic Acids Res. 1994 Nov 11;22(22):4653-9. doi: 10.1093/nar/22.22.4653.
Thermal denaturation profiles of an oligodeoxynucleotide that forms a hairpin structure with a cytidine-rich loop show an unexpected transition at 60 degrees C at pH 5.0 but not at pH 8.0. Analytical ultracentrifugation shows that this transition reflects dimer formation via the interaction of loops from two molecules to form a novel structure termed the h-dimer. The dependence of this structure on low pH implies the formation of cytosine-protonated cytosine base pairs. NMR spectroscopy, thermal denaturation and ultraviolet absorption spectral analysis suggest a similarity to the i-motif structure recently proposed for the interaction of deoxycytidine oligomers. The use of hairpin loops to form i-motif-like structures may prove useful in searches for cognate proteins and possibly in the production of antibodies.
一种形成富含胞嘧啶环的发夹结构的寡脱氧核苷酸的热变性曲线显示，在pH 5.0时于60℃出现意外转变，而在pH 8.0时则未出现。分析超速离心表明，这种转变反映了通过两个分子的环相互作用形成二聚体，形成一种称为h-二聚体的新结构。这种结构对低pH的依赖性意味着形成了胞嘧啶-质子化胞嘧啶碱基对。核磁共振光谱、热变性和紫外吸收光谱分析表明，其与最近提出的用于脱氧胞苷寡聚物相互作用的i-基序结构相似。利用发夹环形成i-基序样结构可能在寻找同源蛋白以及可能在抗体生产中证明是有用的。
