Patterns of cleavages induced by lead ions in defined RNA secondary structure motifs
Patterns of cleavages induced by lead ions in defined RNA secondary structure motifs
复制标题
DOI：
10.1006/jmbi.1997.1462
复制
发表时间：
1998-01-16
影响因子：
5.6
通讯作者：
Krzyzosiak, WJ
中科院分区：
文献类型：
--
作者：
Ciesiolka, J;Michalowski, D;Krzyzosiak, WJ
我们已经表征了各种RNA凸起，环和其他单链序列对Pb2+促进水解的敏感性。突起的反应性主要取决于侧翼碱基对的结构背景，突起5'侧核苷酸的作用特别强。凸起的残基与其相邻残基之间的堆叠相互作用的效率似乎决定了裂解的特异性和效率。二核苷酸和三核苷酸膨出物的水解仅与它们的核苷酸组成有轻微的关系。在末端环的情况下，它们的水解效率通常随着环的大小而增加，并且强烈依赖于它的核苷酸组成。稳定的四联环UUCG， CUUG和GCAA耐水解，而在GNRA家族的其他一些环中，发生单一的弱裂解，表明该家族中存在结构亚类。在低聚体12中，对靠近茎的单链区域的磷酸二酯键的非常有效的特异性水解类似于一些tRNA分子的高度特异性裂解。该反应在Pb2+存在的情况下发生，而在其他几种金属离子存在的情况下则不发生。Pb2+可切割的RNA结构域可以被认为是铅酶的另一个例子。Pb2+诱导的模型RNA低聚物水解的结果应该有助于解释更大的自然存在的RNA分子的裂解模式。(C) 1998学术出版社有限公司
We have characterized the susceptibility of various RNA bulges, loops and other single-stranded sequences to hydrolysis promoted by Pb2+. The reactivity of bulges depends primarily on the structural context of the flanking base-pairs and the effect of nucleotide present at the 5' side of the bulge is particularly strong. The efficiency of stacking interactions between the bulged residue and its neighbors seems to determine cleavage specificity and efficiency. Hydrolysis of two-and three-nucleotide bulges depends only slightly on their nucleotide composition. In the case of terminal loops, the efficiency of their hydrolysis usually increases with the loop size and strongly depends on its nucleotide composition. Stable tetraloops UUCG, CUUG and GCAA are resistant to hydrolysis, while in some other loops of the GNRA family a single, weak cleavage occurs, suggesting the existence of structural subclasses within the family. A very efficient, specific hydrolysis of a phosphodiester bond in the single-stranded region adjacent to the stem in oligomer 12 resembles highly specific cleavages of some tRNA molecules. The reaction occurs in the presence of Pb2+, but not in the presence of several other metal ions. The Pb2+-cleavable RNA domain may be considered another example of lead-zyme. The results of Pb2+-induced hydrolysis in model RNA oligomers should be useful in interpretation of cleavage patterns of much larger, naturally occurring RNA molecules. (C) 1998 Academic Press Limited.