Watanabe K, Kuchino Y, Yamaizumi Z, Kato M, Oshima T, Nishimura S
J Biochem. 1979 Oct;86(4):893-905. doi: 10.1093/oxfordjournals.jbchem.a132621.
The nucleotide sequence of formylmethionine tRNA from an extreme thermophile, Thermus thermophilus HB8, was determined by a combination of classical methods using unlabeled samples to determine the sequences of the oligonucleotides of RNase T1 and RNase A digests and a rapid sequencing gel technique using 5'-32P labeled samples to determine overlapping sequences. Formylmethionine tRNA from T. thermophilus is composed of two species, tRNAf1Met and tRNAf2Met. Their nucleotide sequences are almost identical, and are also almost identical with that of E. coli tRNAfMet, except for slight modifications and replacements. Both species have modifications at three points which do not exist in E. coli tRNAfMet: 2'-O-methylation at G19, N-1-methylation at A59 and 2-thiolation at T55. Moreover U51 in E. coli tRNAfMet is replaced by C51 in both species, so that a G-C pair is formed between this C51 and G65. tRNAf2Met has a reversed G-C pair at positions 52 and 64 compared with those in tRNAf1Met and E. coli tRNAfMet. Other regions are mostly the same as those in all prokaryotic initiator tRNAs so far reported. The thermostability of these thermophile initiator tRNAs is discussed in relation to their unique modifications.
嗜热栖热菌HB8中甲酰甲硫氨酸tRNA的核苷酸序列，是通过结合使用未标记样品的经典方法来确定核糖核酸酶T1和核糖核酸酶A消化产物的寡核苷酸序列，以及使用5'-32P标记样品的快速测序凝胶技术来确定重叠序列而测定的。嗜热栖热菌的甲酰甲硫氨酸tRNA由两种类型组成，即tRNAf1Met和tRNAf2Met。它们的核苷酸序列几乎相同，并且除了有一些轻微的修饰和替换外，也与大肠杆菌的tRNAfMet几乎相同。这两种类型在大肠杆菌tRNAfMet中不存在的三个位点有修饰：G19处的2'-O-甲基化、A59处的N-1-甲基化和T55处的2-硫代化。此外，大肠杆菌tRNAfMet中的U51在这两种类型中均被C51取代，从而在该C51和G65之间形成了一个G-C对。与tRNAfMet和大肠杆菌tRNAfMet相比，tRNAf2Met在52和64位有一个反向的G-C对。其他区域大多与迄今报道的所有原核起始tRNA中的区域相同。这些嗜热菌起始tRNA的热稳定性与其独特的修饰有关，并进行了讨论。
