Shiraishi H, Shimura Y
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
EMBO J. 1988 Dec 1;7(12):3817-21. doi: 10.1002/j.1460-2075.1988.tb03266.x.
The higher-order structure of the RNA component of ribonuclease P from Escherichia coli was analyzed using chemical probes. The secondary structure model which had been constructed from the comparative sequence analysis of the RNA was refined using the experimental data. In a mutant RNA (A89 RNA), which contains a G----A substitution at nucleotide 89, we detected a number of conformational alterations clustered between nucleotides 90 and 239. In view of the fact that A89 RNA is as catalytically active as wild-type RNA, but defective in association with the protein component, it is clear that the catalytic function of the RNA component resides on the structure which is not disrupted by the A89 mutation and that the structures altered by the mutation represent the region(s) interacting with the protein component. Another mutant (A329 RNA), which has a G----A substitution at nucleotide 329 and is defective in catalytic function, showed no detectable change in higher-order structure.
利用化学探针分析了大肠杆菌核糖核酸酶P的RNA组分的高级结构。根据RNA的比较序列分析构建的二级结构模型，利用实验数据进行了优化。在一个突变RNA（A89 RNA）中，其核苷酸89处存在G→A替换，我们检测到许多构象改变集中在核苷酸90至239之间。鉴于A89 RNA与野生型RNA具有相同的催化活性，但与蛋白质组分结合存在缺陷，显然RNA组分的催化功能存在于未被A89突变破坏的结构上，而因突变改变的结构代表了与蛋白质组分相互作用的区域。另一个突变体（A329 RNA），其核苷酸329处存在G→A替换且催化功能有缺陷，在高级结构上未检测到可察觉的变化。
