Ribozyme和靶RNA的相互作用对于切割反应的影响

Effect of interaction between Ribozyme and TargetRNA on the Cleavage Reaction

锤头结构Ｒｉｂｏｚｙｍｅ（Ｒｚ）通过与靶ＲＮＡ上切卢、二狈帕５核普酸序列的碱基配对识别和切割靶ＲＮＡ。通过改变Ｒｉｂｏｚｙｍｅ与靶ＲＮＡ之间碱基配对的长度以及性质，研究了Ｒｉｂｏｚｙｍｅ与靶ＲＮＡ相互作用对于它的切割反应的影响。结果表明：（１）缩短碱基配对长度和改变碱基配对的性质，使Ｒｉｔｉｏｚｙｍｅ与底物的熔卢、（Ｔｍ）降低，同时反应最适温度（Ｔｏｐｔ）也降低。（２）动力学分析表明，反应的Ｋｍ值随温度升高而增加，当温度接近或高于Ｒｉｂｏｚｙｍｅ与底物的熔点时，Ｋｍ值增加大大加快。（３）反应的Ｋｃａｔ也随温度升高而增加，但Ｋｃａｔ增加的速度继而逐渐变慢，最后Ｋｃａｔ下降。

ammerhead ribozyme recognizes and cleaves target RNA by base pairing to sequences of both sides ofcleavage site on target RNA. The effect of the interaction between ribozyme and forget RNA on catulyticefficiency was studied by changing the length of base pairs and the property of double strands in the baseP8iring region. Results revealed that shortening the length of base pairs and changing property in basepairing region caused the decrease of melting temperature and optimal temperature., that km valueincreased gradually as temperature went up and increased greatly as temperature was close to or higher thanTin, and that heat increased as temperature went up while the increase rate of heat slowed down and finallydecreased.