Topper J N, Clayton D A
Department of Developmental Biology, Stanford University School of Medicine, California 94305-5427.
J Biol Chem. 1990 Aug 5;265(22):13254-62.
RNase mitochondrial RNA processing (MRP) is a site-specific endoribonuclease located in both the nucleus and mitochondria of vertebrate cells. The enzyme is a ribonucleoprotein whose RNA component has been shown to be encoded by a nuclear gene. Because RNase MRP is particular in its substrate requirement, RNA-RNA interaction has been proposed as important for the cleavage reaction. A secondary structure of this RNA from mouse cells has been derived by chemical modification of in vivo MRP RNA in ribonucleoprotein form, as isolated free RNA, and as RNA synthesized in vitro. Full-length MRP RNA appears to adopt a conformation containing a significant number of single-stranded residues and may form a pseudoknot. The data are consistent with both the RNA within the ribonucleoprotein and the free RNA possessing comparable secondary structures and suggest a possible site of interaction between enzyme and substrate. The human MRP RNA can be folded into a conformation very similar to that predicted for the mouse MRP RNA. A more limited analysis of human MRP RNA is consistent with the structure proposed for the mouse species.
核糖核酸酶线粒体RNA加工酶（MRP）是一种特异性内切核糖核酸酶，存在于脊椎动物细胞的细胞核和线粒体中。该酶是一种核糖核蛋白，其RNA组分已被证明由一个核基因编码。由于核糖核酸酶MRP对底物的要求较为特殊，因此有人提出RNA-RNA相互作用对切割反应很重要。通过对以核糖核蛋白形式存在的体内MRP RNA、分离得到的游离RNA以及体外合成的RNA进行化学修饰，推导出了小鼠细胞中这种RNA的二级结构。全长MRP RNA似乎采用了一种含有大量单链残基的构象，并且可能形成一个假结。这些数据与核糖核蛋白中的RNA和游离RNA具有相似的二级结构一致，并暗示了酶与底物之间可能的相互作用位点。人类MRP RNA可以折叠成与小鼠MRP RNA预测结构非常相似的构象。对人类MRP RNA的更有限分析与为小鼠物种提出的结构一致。
