STRUCTURAL DOMAINS OF TRANSFER-RNA MOLECULES
STRUCTURAL DOMAINS OF TRANSFER-RNA MOLECULES
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DOI：
10.1126/science.790568
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发表时间：
1976-01-01
期刊：
影响因子：
56.9
通讯作者：
RICH, A
中科院分区：
文献类型：
--
作者：
QUIGLEY, GJ;RICH, A
本文描述了最近对2.5ANG.分辨率的X射线衍射数据进行的精细分析所揭示的酵母tRNAPhe构象的各种详细特征。在未经改进的版本中观察到的分子的大体特征在很大程度上得到了证实，并发现了一些新的特征。核糖2‘’羟基在维持该RNA分子中一系列非螺旋构象方面的独特作用已变得明显。这些特征中的许多都是RNA分子的核糖磷酸骨架几何形状的直接结果，这些特征也可能在其他RNA物种的结构区域中找到。特别关注了这一分析揭示的两个构象基序。这些包括T.psi.C和多核苷酸链中的反密码子发夹转弯之间惊人的相似性，这是通过尿苷在U转弯中的参与而稳定的。此外，在多核苷酸链中经常出现ARCH构象，该构象由从2‘’羟基残基到跨越ARCH碱基的磷酸基团的氢键稳定。在非螺旋区，几乎一半的核糖残基参与O2‘’氢键作用，稳定了分子的构象，这说明了2‘’羟基相互作用在定义三级结构中的重要性。详细描述了在蛋白质合成过程中可能具有相当大功能意义的两个区域。一种涉及T、psi.C和D环的连接，这可能在蛋白质合成过程中经历核糖体的构象变化。另一个区域是反密码子，它似乎在构象上处于稳定状态，准备与单链多核苷酸mRNA相互作用。对分子这一端的分析表明，反密码子可能会与信息相互作用，尽管到目前为止还不足以理解两个tRNA分子如何与信息上相邻的密码子相互作用。
Various detailed features of the conformation of yeast tRNAPhe revealed by recent refinement analysis of X-ray diffraction data at 2.5 .ANG. resolution were described. The gross features of the molecule observed in the unrefined version were largely confirmed and a number of new features found. The unique role of the ribose 2'' hydroxyl groups in maintaining a series of nonhelical conformations in this RNA molecule has become apparent. Many of these features are a direct consequence of the geometry of the ribose phosphate backbone of RNA molecules, and these may also be found in structural regions of other RNA species as well. Special attention was directed toward 2 conformational motifs revealed by this analysis. These include the striking similarity between the T.psi.C and anticodon hairpin turns in the polynucleotide chain, which are stabilized by the participation of uridine in the U turn. In addition, there is frequent occurrence of an arch conformation in the polynucleotide chain which is stabilized by hydrogen bonds from 2'' hydroxyl residues to phosphate groups across the base of the arch. The importance of the 2'' hydroxyl interactions in defining tertiary structure is illustrated by the fact that, in the nonhelical regions, almost half of the ribose residues are involved in O2'' hydrogen-bonding interactions which stabilize the conformation of the molecule. Two regions which may have considerable functional significance during protein synthesis are described in detail. One involves the joining of the T.psi.C and D loops, which may undergo conformational change in the ribosome during protein synthesis. The other region is the anticodon, which seems conformationally poised, ready to interact with a single-stranded polynucleotide mRNA. Analysis of this end of the molecule suggests ways in which the anticodon may interact with the message, although as yet not enough is known to understand how 2 tRNA molecules interact with adjoining codons on the message.