Amiri K M, Hagerman P J
Department of Biochemistry, Biophysics and Genetics, University of Colorado Health Sciences Center, Denver 80262.
Biochemistry. 1994 Nov 15;33(45):13172-7. doi: 10.1021/bi00249a003.
Phylogenetic and biochemical studies of RNA have provided a wealth of information regarding secondary structure; however, knowledge of tertiary structure has been more difficult to obtain. In the current work, electrophoretic and hydrodynamic measurements have yielded the global conformations of a self-cleaving "hammerhead" RNA, both prior to and following self-cleavage. The pre- and post-cleavage structures appear to have nearly identical conformations in which the three helices assume a roughly coplanar arrangement with well-defined interhelix angles. Following self-cleavage, one of the three helix stems (stem I) undergoes a slight (< 10 degrees) realignment, although the relative positions of the other two stems remain unchanged. Extension of stem III from (nominally) three base pairs to nine base pairs, known to dramatically enhance the rate of self-cleavage, results in a substantial (approximately 70 degrees) realignment of stems I and II. The current study represents an approach for studying other nonhelical elements in RNA.
对RNA的系统发育和生化研究已经提供了大量有关二级结构的信息；然而，三级结构的知识却更难获得。在当前的工作中，电泳和流体动力学测量得出了一种自我切割的“锤头状”RNA在自我切割前后的整体构象。切割前和切割后的结构似乎具有几乎相同的构象，其中三个螺旋呈现出大致共面的排列，且螺旋间角度明确。自我切割后，三个螺旋茎之一（茎I）发生了轻微（<10度）的重新排列，尽管其他两个茎的相对位置保持不变。已知将茎III从（名义上的）三个碱基对延长至九个碱基对会显著提高自我切割的速率，这会导致茎I和茎II发生大幅（约70度）的重新排列。当前的研究代表了一种研究RNA中其他非螺旋元件的方法。
