biostudies-literatureUnknown37(21)Moukadiri IThe wobble uridine of certain bacterial and mitochondrial tRNAs is modified, at position 5, through an unknown reaction pathway that utilizes the evolutionarily conserved MnmE and GidA proteins. The resulting modification (a methyluridine derivative) plays a critical role in decoding NNG/A codons and reading frame maintenance during mRNA translation. The lack of this tRNA modification produces a pleiotropic phenotype in bacteria and has been associated with mitochondrial encephalomyopathies in humans. In this work, we use in vitro and in vivo approaches to characterize the enzymatic pathway controlled by the Escherichia coli MnmE*GidA complex. Surprisingly, this complex catalyzes two different GTP- and FAD-dependent reactions, which produce 5-aminomethyluridine and 5-carboxymethylamino-metNucleic acids research7177-93https://www.ebi.ac.uk/biostudies/studies/S-EPMC2790889biostudies-literatureEvolutionarily conserved proteins MnmE and GidA catalyze the formation of two methyluridine derivatives at tRNA wobble positions.PMC2790889Piera JBjork GRMoukadiri IArmengod MEPrado SVelazquez-Campoy AfalseEvolutionarily conserved proteins MnmE and GidA catalyze the formation of two methyluridine derivatives at tRNA wobble positions.The wobble uridine of certain bacterial and mitochondrial tRNAs is modified, at position 5, through an unknown reaction pathway that utilizes the evolutionarily conserved MnmE and GidA proteins. The resulting modification (a methyluridine derivative) plays a critical role in decoding NNG/A codons and reading frame maintenance during mRNA translation. The lack of this tRNA modification produces a pleiotropic phenotype in bacteria and has been associated with mitochondrial encephalomyopathies in humans. In this work, we use in vitro and in vivo approaches to characterize the enzymatic pathway controlled by the Escherichia coli MnmE*GidA complex. Surprisingly, this complex catalyzes two different GTP- and FAD-dependent reactions, which produce 5-aminomethyluridine and 5-carboxymethylamino-met2009-01-01T00:00:00Z2009 Nov2025-04-26T12:40:37.873Z2019-03-27T00:27:17ZS-EPMC27908891976761010.1093/nar/gkp762