Modomics - A Database of RNA Modifications

ID Card:

Full name: Queuine tRNA-ribosyltransferase
Synonym: ZMO0363
GI: 283856241
COG: COG0343
UniProt: P28720
Structures: | 1Q2R | 1Q2S | 1WKF |
Enzyme type: transglycosylase
Position of modification - modification: t:34 - preQ1

PDB Structures:


Structure Description:


Abstract of the PDB Structure's related Publication:

Prokaryotic tRNA guanine transglycosylase (TGT) catalyzes replacement of guanine (G) by 7-aminomethyl-7-deazaguanine (PreQ1) at the wobble position of four specific tRNAs. Addition of 9-deazaguanine (9dzG) to a reaction mixture of Zymomonas mobilis TGT and an RNA substrate allowed us to trap, purify and crystallize a chemically competent covalent intermediate of the TGT-catalyzed reaction. The crystal structure of the TGT-RNA-9dzG ternary complex at a resolution of 2.9 A reveals, unexpectedly, that RNA is tethered to TGT through the side chain of Asp280. Thus, Asp280, instead of the previously proposed Asp102, acts as the nucleophile for the reaction. The RNA substrate adopts an unusual conformation, with four out of seven nucleotides in the loop region flipped out. Interactions between TGT and RNA revealed by the structure provide the molecular basis of the RNA substrate requirements by TGT. Furthermore, reaction of PreQ1 with the crystallized covalent intermediate provides insight into the necessary structural changes required for the TGT-catalyzed reaction to occur.

Download RCSB-PDB Structures:

Pdb Files   1Q2R.pdb   1Q2S.pdb   1WKF.pdb  
Pdbx/mmCIF Files   1Q2R.cif   1Q2S.cif   1WKF.cif  

Protein sequence:



The homologue from E. coli was biochemically characterized.


Title Authors Journal Details PubMed Id DOI
Sequence analysis and overexpression of the Zymomonas mobilis tgt gene encoding tRNA-guanine transglycosylase: purification and biochemical characterization of the enzyme. Reuter K, Ficner R J Bacteriol [details] 7665516 -
Crystal structure of tRNA-guanine transglycosylase: RNA modification by base exchange. Romier C, Reuter K, Suck D, Ficner R EMBO J [details] 8654383 -
Mutagenesis and crystallographic studies of Zymomonas mobilis tRNA-guanine transglycosylase to elucidate the role of serine 103 for enzymatic activity. Gradler U, Ficner R, Garcia GA, Stubbs MT, Klebe G, Reuter K FEBS Lett [details] 10413112 -