3VYW image
Deposition Date 2012-10-03
Release Date 2012-10-17
Last Version Date 2024-10-16
Entry Detail
PDB ID:
3VYW
Keywords:
Title:
Crystal structure of MNMC2 from Aquifex Aeolicus
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.49 Å
R-Value Free:
0.25
R-Value Work:
0.19
R-Value Observed:
0.19
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:MNMC2
Gene (Uniprot):aq_1980
Chain IDs:A, B, C, D
Chain Length:308
Number of Molecules:4
Biological Source:Aquifex aeolicus
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
MSE A MET SELENOMETHIONINE
Primary Citation
Characterization and structure of the Aquifex aeolicus protein DUF752: a bacterial tRNA-methyltransferase (MnmC2) functioning without the usually fused oxidase domain (MnmC1).
J.Biol.Chem. 287 43950 43960 (2012)
PMID: 23091054 DOI: 10.1074/jbc.M112.409300

Abstact

Post-transcriptional modifications of the wobble uridine (U34) of tRNAs play a critical role in reading NNA/G codons belonging to split codon boxes. In a subset of Escherichia coli tRNA, this wobble uridine is modified to 5-methylaminomethyluridine (mnm(5)U34) through sequential enzymatic reactions. Uridine 34 is first converted to 5-carboxymethylaminomethyluridine (cmnm(5)U34) by the MnmE-MnmG enzyme complex. The cmnm(5)U34 is further modified to mnm(5)U by the bifunctional MnmC protein. In the first reaction, the FAD-dependent oxidase domain (MnmC1) converts cmnm(5)U into 5-aminomethyluridine (nm(5)U34), and this reaction is immediately followed by the methylation of the free amino group into mnm(5)U34 by the S-adenosylmethionine-dependent domain (MnmC2). Aquifex aeolicus lacks a bifunctional MnmC protein fusion and instead encodes the Rossmann-fold protein DUF752, which is homologous to the methyltransferase MnmC2 domain of Escherichia coli MnmC (26% identity). Here, we determined the crystal structure of the A. aeolicus DUF752 protein at 2.5 Å resolution, which revealed that it catalyzes the S-adenosylmethionine-dependent methylation of nm(5)U in vitro, to form mnm(5)U34 in tRNA. We also showed that naturally occurring tRNA from A. aeolicus contains the 5-mnm group attached to the C5 atom of U34. Taken together, these results support the recent proposal of an alternative MnmC1-independent shortcut pathway for producing mnm(5)U34 in tRNAs.

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