Crystal Structure of E.coli MnmG (GidA), a Highly-Conserved tRNA Modifying Enzyme
Classification:
RNA BINDING PROTEIN
Technique:
X-Ray Diffraction
Resolution:
2.41
R value free:
0.238
R value observed:
0.203
R value work:
0.201
Abstract of the PDB Structure's related Publication:
The MnmE-MnmG complex is involved in tRNA modification. We have determined the crystal structure of Escherichia coli MnmG at 2.4-A resolution, mutated highly conserved residues with putative roles in flavin adenine dinucleotide (FAD) or tRNA binding and MnmE interaction, and analyzed the effects of these mutations in vivo and in vitro. Limited trypsinolysis of MnmG suggests significant conformational changes upon FAD binding.
Proteins MnmE and MnmG are evolutionary conserved from bacteria to eukaryotic organelles. MnmE and MnmG are dimeric and form a functional α2β2 heterotetrameric complex (MnmEG) in which both proteins are interdependent. MnmG is a FAD- and NADH-binding protein, while instead, MnmE is a GTP- and tetrahydrofolate (THF)-binding protein. The MnmEG heterotetrameric complex catalyzes the addition of the aminomethyl (nm) and carboxymethylaminomethyl (cmnm) groups to position 5 of the wobble uridine using ammonium and glycine, respectively. In E.coli MnmEG complex is involved in the modification of the wobble uridine of tRNALysmnm5s2UUU, tRNAGlncmnm5s2UUG, tRNAArgmnm5UCU, tRNAGlumnm5s2UUC, tRNALeucmnm5UmAA, tRNAGlymnm5UCC. MNMEG modified substrates are neither the starting nor the final products of the catalytic pathway. Indeed, MnmA is involved in the 2-thiolation of the wobble uridine after which MnmEG complex is involved (Moukadiri et al. 2014 ) .
The output of the tRNA modification pathways controlled by the Escherichia coli MnmEG and MnmC enzymes depends on the growth conditions and the tRNA species.
Crystal structures of the conserved tRNA-modifying enzyme GidA: implications for its interaction with MnmE and substrate.
Enzymology of tRNA modification in the bacterial MnmEG pathway.
Evolutionarily conserved proteins MnmE and GidA catalyze the formation of two methyluridine derivatives at tRNA wobble positions.
Further insights into the tRNA modification process controlled by proteins MnmE and GidA of Escherichia coli.
SAXS analysis of the tRNA-modifying enzyme complex MnmE/MnmG reveals a novel interaction mode and GTP-induced oligomerization.
The output of the tRNA modification pathways controlled by the Escherichia coli MnmEG and MnmC enzymes depends on the growth conditions and the tRNA species.
Translational misreading: a tRNA modification counteracts a +2 ribosomal frameshift.