Harris C L, Marashi F
Nucleic Acids Res. 1980 May 10;8(9):2023-37. doi: 10.1093/nar/8.9.2023.
The isoleucine acceptance of tRNA from Escherichia coli C6 was previously shown to be influenced by the synthetase level (Marashi, F. and Harris, C.L. 1977. Biochim. Biophys. Acta 477, 84-88). We show here that the increased acceptance observed at higher enzyme levels is accompanied by an increase in the aminoacylation of one tRNAile species. Hence, tRNAile, a minor species at low enzyme levels, is a major isoacceptor after full aminoacylation. The two major isoleucine species have been purified using a combination of BD-cellulose, DEAE-Sephadex A-50 and methylated albumin kieselguhr chromatography. tRNAile (1511 pmoles ile/A260 of tRNA) was found to be slowly acylated, with 2a Vmax one-seventh that observed with tRNAil3le (1475 pmoles ile/A260). Two-dimensional TLC analysis of RNase T2 digests revealed differences in nucleotide content between the purified tRNAs. These results are discussed in terms of the presence of slow and fast tRNAile species in E. coli.
先前的研究表明，来自大肠杆菌C6的tRNA对异亮氨酸的接纳受合成酶水平的影响（Marashi, F.和Harris, C.L. 1977. 《生物化学与生物物理学报》477, 84 - 88）。我们在此表明，在较高酶水平下观察到的接纳增加伴随着一种tRNAile种类的氨酰化增加。因此，tRNAile在低酶水平时是次要种类，在完全氨酰化后是主要的同工受体。通过结合使用BD - 纤维素、DEAE - 葡聚糖A - 50和甲基化白蛋白硅藻土色谱法，已纯化出两种主要的异亮氨酸种类。发现tRNAile（1511皮摩尔异亮氨酸/tRNA的A260）酰化缓慢，其2a Vmax是tRNAil3le（1475皮摩尔异亮氨酸/tRNA的A260）观察值的七分之一。对核糖核酸酶T2消化产物的二维薄层层析分析揭示了纯化的tRNA之间核苷酸含量的差异。根据大肠杆菌中存在慢速和快速tRNAile种类对这些结果进行了讨论。
