Magarshak Iu B
Courant Institute of Mathematical Sciences, New York, USA.
Biofizika. 1997 Nov-Dec;42(6):1216-23.
In [1], the existence of two competing secondary structures at the 5'-end of Leptomonas collosoma spliced leader RNA was shown. On going from one steady-state secondary structure to the other, and vice versa, RNA passes through several states in which the chain gets tied up into nodes. If the transitions are reversible, the nodes are figurative both in the forth and back directions although the secondary structures that arise in this process are quite different, and the forth and back routs do not coincide. It is assumed that under certain conditions, the chain can get tied into the next node of series 5(2), which most likely will not get untied. This node is tightened around GG nucleotides. In this case, the migration of the gap is possible, as a result of which the chain can break. Independent experiments indicate that the RNA chain breaks just at this site upon splicing. Based on these results, a possible role of nodes in the enzymatic activity is discussed.
在[1]中，已表明在粗短膜鞭毛虫剪接前导RNA的5'端存在两种相互竞争的二级结构。从一种稳态二级结构转变为另一种，反之亦然时，RNA会经历几个状态，在此过程中链会缠结形成节点。如果转变是可逆的，那么尽管在此过程中产生的二级结构截然不同，并且向前和向后的路径也不重合，但节点在向前和向后的方向上都是虚拟的。据推测，在某些条件下，链可能会缠结到5(2)系列的下一个节点中，而这个节点很可能不会解开。该节点围绕GG核苷酸收紧。在这种情况下，缺口可能会迁移，结果链可能会断裂。独立实验表明，RNA链在剪接时恰好在这个位点断裂。基于这些结果，讨论了节点在酶活性中的可能作用。
