Modification at the C5 of the wobble uridine in Bacillus subtilis tRNAs

Abstract

In Bacillus subtilis, 5-methoxy uridine (mo5U) by wobble uridine modification at the C5 in tRNAAla, tRNAPro, tRNAThr, tRNASer, tRNAVal, tRNALeu is important for facilitating non-Watson-Crick base pairing to expand the decoding capacity of tRNAs. In B. subtilis, uridine at the wobble position is modified to 5-hydroxy uridine (ho5U) by O2 dependent hydroxylase YbfQ or prephenate dependent hydroxylases TrhP1 and TrhP2. Sequentially, hydroxyl group of the ho5U is methylated by TrmR, a Sadenosyl-l-methionine (SAM)-dependent methyltransferase, forming the mo5U. However, the molecular mechanism of the enzymes related to hydroxylation of wobble uridine have not been fully understood. We confirmed in vitro hydroxylation activity by B. subtilis YbfQ with full-length tRNAAla and anticodon stemloop of tRNAAla, tRNAThr, tRNAPro. Further, we have identified that a feature of ∆trmR phenotype is related to cell mobility via Stable isotope labeling by amino acids in cell culture (SILAC) based proteome quantitative analylsis.