Skip to main content
. Author manuscript; available in PMC: 2023 May 19.
Published in final edited form as: Methods Enzymol. 2020 Apr 20;641:373–399. doi: 10.1016/bs.mie.2020.03.009

Fig. 3.

Fig. 3

Catalytic mechanism and binding interactions of bacterial TGT with guanine and preQ1. E. coli numbering is used. (A) Asp264 acts as a nucleophile to attack the anomeric carbon of ribose 34, breaking the N–C glycosidic linkage. (B) A covalent TGT-RNA covalent intermediate is formed. (C) preQ1 replaces guanine in the binding pocket, assisted by a conformational change of the Leu215/Ala216 peptide bond. (D) N9 of preQ1 acts as a nucleophile to reform a glycosidic bond with ribose 34.