Randles J W, Steger G, Riesner D
Nucleic Acids Res. 1982 Sep 25;10(18):5569-86. doi: 10.1093/nar/10.18.5569.
The conformational transitions of viroid-like RNAs associated with cadang-cadang disease, velvet tobacco mottle virus, and solanum nodiflorum mottle virus were studied by melting analysis and fast temperature jump technique in 1 mM sodium-cacodylate, 10 mM NaCl, 0.1 mM EDTA, pH 6.8. The 4 circular RNAs of cadang-cadang show a highly cooperative transition between 45 and 49 degrees C, respectively, and a second transition of less hypochromicity at about 10 degrees C higher temperatures. The data are interpreted quantitatively on the basis of the sequences and secondary structure models. A very similar scheme for the structure and structural transitions as derived earlier for other viroids applies to the cadang-cadang RNAs. In the main transition the total native secondary structure is disrupted and a stable hairpin consisting of 9 base pairs is newly formed which dissociates in the second transition. The thermal denaturation of the circular RNAs from the viruses mentioned above is clearly distinct from viroid RNA in respect to stability and cooperativity. The results on cadang-cadang RNA are discussed in the light of recent hypotheses about the interference of viroids with the splicing process of the host cell.
采用熔解分析和快速温度跳跃技术，在1 mM 二甲胂酸钠、10 mM 氯化钠、0.1 mM 乙二胺四乙酸、pH 6.8的条件下，研究了与可可椰子枯死病、绒毛烟草斑驳病毒和节花茄斑驳病毒相关的类病毒样RNA的构象转变。可可椰子枯死病的4种环状RNA分别在45至49摄氏度之间呈现高度协同转变，在大约高10摄氏度的温度下出现第二次低增色性转变。根据序列和二级结构模型对数据进行了定量解释。先前推导的适用于其他类病毒的结构及结构转变的非常相似的方案，也适用于可可椰子枯死病RNA。在主要转变中，总的天然二级结构被破坏，新形成了一个由9个碱基对组成的稳定发夹结构，该结构在第二次转变中解离。上述病毒的环状RNA的热变性在稳定性和协同性方面明显不同于类病毒RNA。根据最近关于类病毒对宿主细胞剪接过程干扰的假说，对可可椰子枯死病RNA的结果进行了讨论。
