Fig. 6: The hypothetical multi-step tRNA recognition mechanism of ADAT2/3.
a Ligand-free enzyme state: in the free ADAT2/3 heterodimer ADAT2C is disordered and ADAT3N is flexibly linked. b Initial capture: the RNA recognition motifs in ADAT3N and in ADAT2C capture RNA; tRNAs are progressively guided by the extension of favorable interactions towards the anticodon binding cleft; hereby non-tRNA architectures will be rejected. c Anticodon loop insertion into the active site: The anticodon loop enters the active-site cleft through the RY-gate, and ADAT2C folds into the major groove of the anticodon loop to position the ligand for the reaction. d Substrate release: Detachment of the individual RNA-binding motifs initiates tRNA release.
