Abstract
Transfer RNAs (tRNAs) are the most ancient RNA molecules in the cell, modification pattern of which is linked to phylogeny. The aim of this study was to determine the tRNA modification profiles of obligate (Anoxybacillus, Geobacillus, Paragebacillus) and moderate (Bacillus, Brevibacillus, Ureibacillus, Paenibacillus) thermophilic aerobic bacilli strains to find out its linkage to phylogenetic variations between species. LC-MS was applied for the quantification of modified nucleosides using both natural and isotopically labeled standards. The presence of m2A and m7G modifications at high levels was determined in all species. Relatively high level of i6A and m5C modification was observed for Paenibacillus and Ureibacillus, respectively. The lowest level of Cm modification was found in Bacillus. The modification ms2i6A and m1G were absent in Brevibacillus and Ureibacillus, respectively, while modifications Am and m22G were observed only for Ureibacillus. While both obligate and moderate thermophilic species contain Gm, m1G and ms2i6A modifications, large quantities of them (especially Gm and ms2i6A modification) were detected in obligate thermophilic ones (Geobacillus, Paragebacillus and Anoxybacillus). The collective set of modified tRNA bases is genus-specific and linked to the phylogeny of bacilli. In addition, the dataset could be applied to distinguish obligate thermophilic bacilli from moderate ones.