CATH Classification

Domain Context

CATH Clusters

Superfamily Queuine tRNA-ribosyltransferase-like
Functional Family Queuine tRNA-ribosyltransferase

Enzyme Information
tRNA-guanine(34) transglycosylase.
based on mapping to UniProt P28720
(1) Guanine(34) in tRNA + queuine = queuosine(34) in tRNA + guanine. (2) Guanine(34) in tRNA + 7-aminomethyl-7-carbaguanine = 7-aminomethyl-7- carbaguanine(34) in tRNA + guanine.
-!- Certain prokaryotic and eukaryotic tRNAs contain the modified base queuine at position 34. -!- In eukaryotes queuine is salvaged from food and incorporated into tRNA directly via a base-exchange reaction, replacing guanine. -!- In eubacteria, which produce queuine de novo, the enzyme catalyzes the exchange of guanine with the queuine precursor preQ(1), which is ultimately modified to queuine. -!- The eubacterial enzyme can also use an earlier intermediate, preQ(0), to replace guanine in unmodified tRNA(Tyr) and tRNA(Asn). -!- This enzyme acts after EC in the queuine-biosynthesis pathway.

UniProtKB Entries (1)

Zymomonas mobilis subsp. mobilis ZM4 = ATCC 31821
Queuine tRNA-ribosyltransferase

PDB Structure

External Links
Organism Escherichia
Primary Citation
Glutamate versus glutamine exchange swaps substrate selectivity in tRNA-guanine transglycosylase: insight into the regulation of substrate selectivity by kinetic and crystallographic studies.
Tidten, N., Stengl, B., Heine, A., Garcia, G.A., Klebe, G., Reuter, K.