运用原子力显微镜研究核糖体RNA的二级结构

Secondary Structure of Rat Ribosomal RNAs Studied by Atomic Force Microscope

通过反复冻融的方法使核糖体在低温下瓦解 ,制备了rRNA ,不经抽提、变性和染色处理就能使rRNA在云母表面上较好地分散 .用原子力显微镜对其进行观察 ,发现rRNA分子呈多分支的棒状结构 ,且有很好的规律性 .根据RNAs的大小和形状可将其分为三种 ,它们分别与计算机所预测的2 8S 5 8S、 1 8S、 5SrRNA的二级结构相似 .我们得到的 2 8S 5 8S、 1 8S、 5 8S、 5SrRNAs的结构信息 ,支持基于热力学考虑推测的rRNAs的二级结构 .

Rat liver ribosomal RNAs on surfaces of mica were imaged by atomic force microscope (AFM) under ambient condition. A number of images of 28S-58S、18S、5S rRNAs were obtained directly. The rRNAs were prepared by thawing the solution of low concentration of ribosomes repeatedly to crumble the ribosomes. The rRNAs were scattered on surface of mica very well. The rRNAs prepared by this method were always in three forms when they were scattered on surface of mica. The structures of the three forms of rRNAs were consistent with the established models by computer for 28S-58S、18S、5S rRNAs respectively. The result supports the models of the secondary structures of rRNAs considered by the thermodynamic principle. It is demonstrated that AFM could provide valuable three-dimensional information of rRNAs.