Spencer D F, Bonen L, Gray M W
Biochemistry. 1981 Jul 7;20(14):4022-9. doi: 10.1021/bi00517a011.
Using the procedures of Donis-Keller et al. [Donis-Keller, H., Maxam, A. M., & Gilbert, W. (1977) Nucleic Acids Res. 4, 2527--2538 (1977)] and Peattie [Peattie, D. A. (1979) Proc. Natl. Acad. Sci. U.S.A. 76, 1760--1764], we have determined the nucleotide sequence of wheat mitochondrial 5S ribosomal ribonucleic acid (rRNA). This sequence [Formula: see text] is the first to be reported for a plant mitochondrial RNA. A highly conserved region (underlined) readily identifies the molecule as a structural homologue of other 5S rRNAs, as do potential base-paired regions which are characteristic of all known (prokaryotic, chloroplast, eukaryotic cytosol) 5S rRNA sequences. However, when assessed in terms of those structural features which distinguish prokaryotic from eukaryotic 5S rRNAs, wheat mitochondrial 5S rRNA cannot be classified readily as one or the other but instead displays characteristics of both types. In addition, the mitochondrial 5S rRNA has several unusual features, including (i) a variable number (two to three) of A residues at both the 5' and 3' ends, (ii) a unique sequence (CGACC, italic) in place of the prokaryotic sequence (CGAAC) which has been postulated to interact with aminoacyl-tRNA during translation, and (iii) a novel sequence, AUAUAUAU, immediately following the highly conserved sequence. In terms of overall primary sequence, wheat mitochondrial and cytosol 5S rRNAs seem to be slightly more divergent from each other than either is from Escherichia coli 5S rRNA, with which they are about equally homologous. From these observations, we propose that wheat mitochondrial 5S rRNA represents a distinct class of 5S rRNA. Our observations raise a number of questions about the evolutionary origin and functional role(s) of plant mitochondrial 5S rRNA.
运用多尼斯 - 凯勒等人[多尼斯 - 凯勒，H.，马克萨姆，A. M.，& 吉尔伯特，W.（1977年）《核酸研究》4，2527 - 2538（1977年）]以及皮蒂[皮蒂，D. A.（1979年）《美国国家科学院院刊》76，1760 - 1764]的方法，我们测定了小麦线粒体5S核糖体核糖核酸（rRNA）的核苷酸序列。该序列[公式：见正文]是首次报道的植物线粒体RNA序列。一个高度保守的区域（下划线标注）很容易将该分子识别为其他5S rRNA的结构同源物，潜在的碱基配对区域也是如此，这些区域是所有已知（原核、叶绿体、真核细胞质）5S rRNA序列的特征。然而，根据区分原核和真核5S rRNA的那些结构特征来评估时，小麦线粒体5S rRNA不能轻易地归为其中一类，而是同时展现出两类的特征。此外，线粒体5S rRNA有几个不寻常的特征，包括：（i）5'和3'末端的A残基数量可变（两个到三个）；（ii）一个独特的序列（CGACC，斜体）取代了原核序列（CGAAC），据推测该原核序列在翻译过程中与氨酰 - tRNA相互作用；（iii）一个新序列，AUAUAUAU，紧接在高度保守序列之后。就整体一级序列而言，小麦线粒体和细胞质5S rRNA彼此之间的差异似乎比它们与大肠杆菌5S rRNA的差异略大，它们与大肠杆菌5S rRNA的同源性大致相同。基于这些观察结果，我们提出小麦线粒体5S rRNA代表了一类独特的5S rRNA。我们的观察结果引发了许多关于植物线粒体5S rRNA的进化起源和功能作用的问题。
