Rudinger J, Florentz C, Dreher T, Giegé R
UPR Structure des Macromolécules Biologiques et Mécanismes de Reconnaissance, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France.
Nucleic Acids Res. 1992 Apr 25;20(8):1865-70. doi: 10.1093/nar/20.8.1865.
Mischarging of the valine specific tRNA-like structure of turnip yellow mosaic virus (TYMV) RNA has been tested in the presence of purified arginyl-, aspartyl-, histidinyl-, and phenylalanyl-tRNA synthetases from bakers' yeast. Important mischarging of a 264 nucleotide-long transcript was found with histidinyl-tRNA synthetase which can acylate this fragment up to a level of 25% with a loss of specificity (expressed as Vmax/KM ratios) of only 100 fold as compared to a yeast tRNA(His) transcript. Experiments on transcripts of various lengths indicate that the minimal valylatable fragment (n = 88) is the most efficient substrate for histidinyl-tRNA synthetase, with kinetic characteristics similar to those found for the control tRNA(His) transcript. Mutations in the anticodon or adjacent to the 3' CCA that severely affect the valylation capacity of the 264 nucleotide long TYMV fragment are without negative effect on its mischarging, and for some cases even improve its efficiency. A short fragment (n = 42) of the viral RNA containing the pseudoknot and corresponding to the amino acid accepting branch of the molecule is an efficient histidine acceptor.
在存在来自面包酵母的精氨酰 -、天冬氨酰 -、组氨酰 - 和苯丙氨酰 - tRNA合成酶的情况下，对芜菁黄花叶病毒（TYMV）RNA的缬氨酸特异性类tRNA结构的错载进行了测试。发现组氨酰 - tRNA合成酶对一个264个核苷酸长的转录本有重要的错载现象，该酶可以将这个片段酰化至25%的水平，与酵母tRNA（His）转录本相比，特异性丧失（以Vmax/KM比值表示）仅为100倍。对不同长度转录本的实验表明，最小的可缬氨酰化片段（n = 88）是组氨酰 - tRNA合成酶最有效的底物，其动力学特征与对照tRNA（His）转录本相似。反密码子或3' CCA附近的突变严重影响264个核苷酸长的TYMV片段的缬氨酰化能力，但对错载没有负面影响，在某些情况下甚至提高了其效率。病毒RNA的一个短片段（n = 42），包含假结且对应于分子的氨基酸接受分支，是一种有效的组氨酸受体。
