8omr

Structural highlights

Function

TGT_HUMAN 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:11255023, PubMed:20354154). 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).[UniProtKB:P28720][HAMAP-Rule:MF_03218]^{[1] [2]}

See Also

• TRNA-guanine transglycosylase 3D structures

References

1. ↑ Deshpande KL, Katze JR. Characterization of cDNA encoding the human tRNA-guanine transglycosylase (TGT) catalytic subunit. Gene. 2001 Mar 7;265(1-2):205-12. PMID:11255023
2. ↑ Chen YC, Kelly VP, Stachura SV, Garcia GA. Characterization of the human tRNA-guanine transglycosylase: confirmation of the heterodimeric subunit structure. RNA. 2010 May;16(5):958-68. doi: 10.1261/rna.1997610. Epub 2010 Mar 30. PMID:20354154 doi:http://dx.doi.org/10.1261/rna.1997610