Bhattacharyya A, Murchie A I, Lilley D M
Department of Biochemistry, The University, Dundee, UK.
Nature. 1990 Feb 1;343(6257):484-7. doi: 10.1038/343484a0.
RNA molecules typically exhibit extensive secondary structure, including double-stranded duplex, hairpins, internal loops, bulged bases and pseudoknotted structures (reviewed in refs 3 and 4). This is intimately connected with biological function, including splicing reactions and ribozyme activity. The formation of RNA-DNA hybrids is important in the transcription of DNA, reverse transcription of viral RNA, and DNA replication. Bulged bases in RNA helices are potentially significant in RNA folding and in providing sites for specific protein-RNA interactions, as illustrated by TFIIIA of Xenopus and the coat protein of phage R17. Most information about the structure of RNA derives from fibre diffraction or crystallography of natural molecules, notably transfer RNA, but until recently there have been few systematic studies of RNA structure using designed sequences. We have used gel electrophoresis to investigate the properties of bulged bases in both RNA and RNA-DNA depending on the number and types of bases in the bulge and its position in the fragment. By varying the spacing between two bulge-induced kinks, we have measured the periodicity of RNA and RNA-DNA helices in solution.
RNA分子通常呈现出广泛的二级结构，包括双链双链体、发夹结构、内环、凸起碱基和假结结构（参考文献3和4中有综述）。这与生物学功能密切相关，包括剪接反应和核酶活性。RNA-DNA杂交体的形成在DNA转录、病毒RNA逆转录和DNA复制中很重要。RNA螺旋中的凸起碱基在RNA折叠以及为特定蛋白质-RNA相互作用提供位点方面可能具有重要意义，如非洲爪蟾的TFIIIA和噬菌体R17的外壳蛋白所示。关于RNA结构的大多数信息来自天然分子的纤维衍射或晶体学，特别是转运RNA，但直到最近，使用设计序列对RNA结构进行的系统研究还很少。我们利用凝胶电泳研究了RNA和RNA-DNA中凸起碱基的性质，这取决于凸起中碱基的数量和类型及其在片段中的位置。通过改变两个由凸起诱导的扭结之间的间距，我们测量了溶液中RNA和RNA-DNA螺旋的周期性。
