Published on Dec. 2, 2016 in Nucleic Acids Research volume 45(4): 2124–2136.
PubMed ID: 5389704
Transfer RNA modifications play pivotal roles in pro- 66 tein synthesis. N -threonylcarbamoyladenosine (t A) and its derivatives are modifications found at po- sition 37, 3′-adjacent to the anticodon, in tRNAs responsible for ANN codons. These modifications are universally conserved in all domains of life. t6A and its derivatives have pleiotropic functions in protein synthesis including aminoacylation, de- coding and translocation. We previously discovered a cyclic form of t6 A (ct6 A) as a chemically labile derivative of t6A in tRNAs from bacteria, fungi, plants and protists. Here, we report 2-methylthio cyclic t6A 266 (ms ct A), a novel derivative of ct A found in tRNAs from Bacillus subtilis, plants and Trypanosoma bru- cei. In B. subtilis and T. brucei, ms2ct6A disappeared and remained to be ms2 t6 A and ct6 A by depletion of tcdA and mtaB homologs, respectively, demonstrat- ing that TcdA and MtaB are responsible for biogene- sis of ms2ct6A.