MiaA (Rv2727c) mediated tRNA isopentenylation of Mycobacterium tuberculosis H37Rv.

tRNA modifications play a significant role in the structural stability as well as translational fidelity in all organisms from bacteria to humans. They also play a major role in bacterial physiology by regulating translation in response to various environmental stresses. Modifications coming at the anticodon-stem loop (ASL) are particularly important as they stabilize codon-anticodon interactions, ensuring accuracy and speed in decoding mRNAs Addition of isopentenyl group (i6A) at A37 position by tRNA isopentenyltransferase (MiaA) is a well conserved modification from bacteria to human. We studied M. tuberculosis MiaA from strain H37Rv and identified the target tRNAs for this modification based on the A36A37A38 motif. i6A modification of target tRNAs tRNA(Leu)CAA, tRNA(Phe)GAA, tRNA(Trp)CCA and tRNA(Ser)CGA were further confirmed by isopentenyltransferase assay providing the substrate DMAPP and recombinant MiaA enzyme.