Tanaka Y, Sakamoto T, Sasa K, Kuwabara T, Kim M H, Kurihara Y, Katahira M, Uesugi S
Department of Bioengineering, Faculty of Engineering, Yokohama National University, Japan.
Nucleic Acids Symp Ser. 1997(37):309-10.
Hepatitis delta virus (HDV) RNA ribozyme system which consists of three RNA oligomer strands (substrate 8-mer; enzyme 16-mer plus 35-mer, Fig. 1) was designed. Effects of Mg2+ concentration on the pseudo first-order rate constant (kobs) of RNA cleavage reaction and on conformation of ribozyme complex were examined. The secondary structure of the complex was also analyzed by limited digestion with ribonucleases. The kobs and CD data were analyzed by curve-fitting analysis using equations derived for two-Mg2+ and three-Mg2+ ion binding models. The result revealed that a three-Mg2+ binding model can explain the Mg(2+)-concentration-dependent changes of both conformation and activity of the HDV ribozyme.
设计了由三条RNA寡聚体链（底物8聚体；酶16聚体加35聚体，图1）组成的丁型肝炎病毒（HDV）RNA核酶系统。研究了Mg2+浓度对RNA切割反应的伪一级速率常数（kobs）以及核酶复合物构象的影响。还通过用核糖核酸酶进行有限消化来分析复合物的二级结构。使用从二价镁离子和三价镁离子结合模型推导的方程，通过曲线拟合分析对kobs和圆二色（CD）数据进行了分析。结果表明，三价镁离子结合模型可以解释HDV核酶构象和活性的镁离子浓度依赖性变化。
