6h62

Structural highlights

Function

TGT_MOUSE Catalytic subunit of the queuine tRNA-ribosyltransferase (TGT) that catalyzes the base-exchange of a guanine (G) residue with queuine (Q) at position 34 (anticodon wobble position) in tRNAs with GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr), resulting in the hypermodified nucleoside queuosine (7-(((4,5-cis-dihydroxy-2-cyclopenten-1-yl)amino)methyl)-7-deazaguanosine) (PubMed:19414587, PubMed:29862811). Catalysis occurs through a double-displacement mechanism. The nucleophile active site attacks the C1' of nucleotide 34 to detach the guanine base from the RNA, forming a covalent enzyme-RNA intermediate. The proton acceptor active site deprotonates the incoming queuine, allowing a nucleophilic attack on the C1' of the ribose to form the product (By similarity).[HAMAP-Rule:MF_03218]^{[1] [2]}

See Also

• TRNA-guanine transglycosylase 3D structures

References

1. ↑ Boland C, Hayes P, Santa-Maria I, Nishimura S, Kelly VP. Queuosine formation in eukaryotic tRNA occurs via a mitochondria-localized heteromeric transglycosylase. J Biol Chem. 2009 Jul 3;284(27):18218-27. doi: 10.1074/jbc.M109.002477. Epub 2009, May 4. PMID:19414587 doi:http://dx.doi.org/10.1074/jbc.M109.002477
2. ↑ Behrens C, Biela I, Petiot-Becard S, Botzanowski T, Cianferani S, Sager CP, Klebe G, Heine A, Reuter K. Homodimer architecture of QTRT2, the noncatalytic subunit of the eukaryotic tRNA-guanine transglycosylase. Biochemistry. 2018 Jun 4. doi: 10.1021/acs.biochem.8b00294. PMID:29862811 doi:http://dx.doi.org/10.1021/acs.biochem.8b00294