Watanabe K, Oshima T, Iijima K, Yamaizumi Z, Nishimura S
J Biochem. 1980 Jan;87(1):1-13. doi: 10.1093/oxfordjournals.jbchem.a132713.
Three species of methionine tRNAs and phenylalanine, tyrosine, and isoleucine tRNAs were purified from an extreme thermophile, Thermus thermophilus HB8. Formylation studies of the three methionine tRNAs and their codon-specific binding activities to ribosomes showed that two of them (named tRNAf1Met and tRNAf2Met) were initiator tRNAs and the other (named tRNAmMet) was a non-initiator. The tRNAs from T. thermophilus all had melting temperatures of up to ten degrees higher than the corresponding species from E. coli. Most of the species also had slightly higher G+C contents than the corresponding species of E. coli, and each of them contained one mol each of the modified nucleosides, O2'-methylguanosine (Gm), 2-thioribothymidine (s2T), and 1-methyladenosine (m1A). Their high melting temperatures could be explained by their high G+C contents and the presence of the modified nucleosides, espically s2T. Comparison of the melting temperatures of T. thermophilus tRNAf2Met with those of E. coli tRNAfMet and tRNAmMet at different magnesium concentrations showed that magnesium was also a factor in the thermostability of the thermophile tRNA.
从嗜热栖热菌HB8（Thermus thermophilus HB8）中纯化出了三种甲硫氨酸tRNA以及苯丙氨酸、酪氨酸和异亮氨酸tRNA。对这三种甲硫氨酸tRNA的甲酰化研究及其对核糖体的密码子特异性结合活性表明，其中两种（命名为tRNAf1Met和tRNAf2Met）是起始tRNA，另一种（命名为tRNAmMet）是非起始tRNA。嗜热栖热菌的tRNA的解链温度都比大肠杆菌相应种类的tRNA高出多达10摄氏度。大多数种类的G+C含量也略高于大肠杆菌的相应种类，并且它们各自都含有一摩尔的修饰核苷，即O2'-甲基鸟苷（Gm）、2-硫代胸苷（s2T）和1-甲基腺苷（m1A）。它们较高的解链温度可以用其高G+C含量以及修饰核苷（特别是s2T）的存在来解释。在不同镁浓度下，对嗜热栖热菌tRNAf2Met与大肠杆菌tRNAfMet和tRNAmMet的解链温度进行比较表明，镁也是嗜热菌tRNA热稳定性的一个因素。
