Horie N, Hara-Yokoyama M, Yokoyama S, Watanabe K, Kuchino Y, Nishimura S, Miyazawa T
Biochemistry. 1985 Oct 8;24(21):5711-5. doi: 10.1021/bi00342a004.
From Thermus thermophilus HB8 grown at 65 degrees C, two major tRNAIle species have been purified by column chromatography and polyacrylamide gel electrophoresis. The nucleotide sequence of one of these two tRNAIle1 species (tRNAIle1a) has been determined to be pGGGCGAUUAGCUCAGCUGmGUDAGAGCGCACGCCUGAUt6AAGCGUGAGm7GUCGGUGGs2T psi CAm1AGUCCACCAUCGCCCACCAOH. The nucleotide sequence of the other species (tRNAIle1b) is found to be the same as that of tRNAIle1a except for the modification in position 54; tRNAIle1a has s2T(54) while tRNAIle1b has T(54). The melting temperature of tRNAIle1a is as high as 86.2 degrees C while that of tRNAIle1b is 83.3 degrees C. The single replacement of an oxygen atom (2-carbonyl oxygen) of T(54) by a sulfur atom significantly contributes to the thermostability of the tRNAIle1a species. In addition, the methylation of G(18) and A(58) possibly contributes to the thermostability of T. thermophilus tRNAIle1a and tRNAIle1b species.
从在65摄氏度下生长的嗜热栖热菌HB8中，通过柱色谱法和聚丙烯酰胺凝胶电泳纯化出了两种主要的异亮氨酸转运RNA（tRNAIle）。已确定这两种tRNAIle1中的一种（tRNAIle1a）的核苷酸序列为pGGGCGAUUAGCUCAGCUGmGUDAGAGCGCACGCCUGAUt6AAGCGUGAGm7GUCGGUGGs2TψCAm1AGUCCACCAUCGCCCACCAOH。发现另一种（tRNAIle1b）的核苷酸序列与tRNAIle1a相同，只是在第54位的修饰有所不同；tRNAIle1a在第54位是s2T，而tRNAIle1b在第54位是T。tRNAIle1a的解链温度高达86.2摄氏度，而tRNAIle1b的解链温度为83.3摄氏度。T（54）的一个氧原子（2-羰基氧）被硫原子单取代显著提高了tRNAIle1a的热稳定性。此外，G（18）和A（58）的甲基化可能有助于嗜热栖热菌tRNAIle1a和tRNAIle1b的热稳定性。
