F
IPR004803

tRNA-guanine transglycosylase

InterPro entry
Short nameTGT
Overlapping
homologous
superfamilies
 

Description

Queuine is a hypermodified base that occurs in the wobble position of the anticodon of tRNAs Asp, Asn, His and Tyr. Queuine is incorporated into tRNA via a base exchange reaction with guanine catalysed by queuine tRNA-ribosyltransferase (also known as tRNA-guanine transglycosylase). In eukaryotes, queuine is directly exchanged into tRNA while in eubacteria, a queuine precursor (preQ1) is incorporated and ultimately modified to queuine
[3, 4]
. Archaea contain a closely related enzyme (
IPR004804
) that catalyses a base exchange of guanine for an archaeosine precursor
[5]
. This precursor is then subsequently converted to the archaeal-specific modified base archaeosine. Some archaea, such as Archaeoglobus fulgidus, contain both these enzymes.

The eukaryotic tRNA-guanine transglycosylase exists as a heterodimer of a catalytic subunit (QTRT1) and another subunit known as queuine tRNA-ribosyltransferase domain-containing 1 (QTRTD1), whereas the eubacteria enzyme is homodimeric
[1, 2]
.

References

1.Characterization of cDNA encoding the human tRNA-guanine transglycosylase (TGT) catalytic subunit. Deshpande KL, Katze JR. Gene 265, 205-12, (2001). View articlePMID: 11255023

2.Characterization of the human tRNA-guanine transglycosylase: confirmation of the heterodimeric subunit structure. Chen YC, Kelly VP, Stachura SV, Garcia GA. RNA 16, 958-68, (2010). View articlePMID: 20354154

3.Biosynthesis of the 7-deazaguanosine hypermodified nucleosides of transfer RNA. Iwata-Reuyl D. Bioorg. Chem. 31, 24-43, (2003). View articlePMID: 12697167

4.Role of aspartate 143 in Escherichia coli tRNA-guanine transglycosylase: alteration of heterocyclic substrate specificity. Todorov KA, Garcia GA. Biochemistry 45, 617-25, (2006). View articlePMID: 16401090

5.Hypermodification of tRNA in Thermophilic archaea. Cloning, overexpression, and characterization of tRNA-guanine transglycosylase from Methanococcus jannaschii. Bai Y, Fox DT, Lacy JA, Van Lanen SG, Iwata-Reuyl D. J. Biol. Chem. 275, 28731-8, (2000). View articlePMID: 10862614

GO terms

Cross References

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