Kent O, Chaulk S G, MacMillan A M
Department of Biochemistry, University of Alberta, 4-74 Medical Sciences Building, Edmonton, Alberta, T6G 2C6, Canada.
J Mol Biol. 2000 Dec 15;304(5):699-705. doi: 10.1006/jmbi.2000.4263.
The biological activity of large RNAs is dependent on the formation of complex folded structures that determine function. Typically the creation of such structures requires divalent magnesium and in many cases the folding process takes place over the course of several minutes. It has been proposed that the folding paths of large RNAs proceed through discrete intermediates but the nature of these intermediates is not known in most cases. Here, we describe our studies on the folding of the M1 RNA sub-unit of Escherichia coli RNase P. We performed kinetic footprinting studies of M1 RNA folding with the chemical footprinting reagent peroxynitrous acid to provide a detailed description of the folding pathway of RNase P RNA. Our results indicate that, in contrast to the Group I ribozyme, the M1 RNA folds into its catalytically active structure through the formation of two separately folded domains and that the folding of each proceeds through a discrete series of intermediates. Similar rates of folding were observed for regions believed to form the interface between the two domains. This observation is consistent with a kinetic trap which occurs by interaction of the domains during folding.
大RNA的生物活性取决于决定其功能的复杂折叠结构的形成。通常，此类结构的形成需要二价镁，并且在许多情况下，折叠过程会持续几分钟。有人提出，大RNA的折叠路径是通过离散的中间体进行的，但在大多数情况下，这些中间体的性质尚不清楚。在此，我们描述了我们对大肠杆菌核糖核酸酶P的M1 RNA亚基折叠的研究。我们用化学足迹试剂过氧亚硝酸对M1 RNA折叠进行了动力学足迹研究，以详细描述核糖核酸酶P RNA的折叠途径。我们的结果表明，与I组核酶不同，M1 RNA通过形成两个分别折叠的结构域折叠成其催化活性结构，并且每个结构域的折叠都通过一系列离散的中间体进行。对于被认为形成两个结构域之间界面的区域，观察到了相似的折叠速率。这一观察结果与折叠过程中结构域相互作用导致的动力学陷阱一致。
