a. Surface representation of the TSEN complex with a cartoon of the pre-tRNA, showing significant interaction between TSEN54 and multiple regions of the pre-tRNA. Colors: exons (dark grey), intron (light grey), TSEN54 (teal), TSEN34 (pink), TSEN2 (orange), TSEN15 (blue). b. Cloverleaf 2D tRNA structure with selected TSEN interfaces labeled. TSEN-tRNA interfaces mediated by hydrogen bonds and hydrophobic contacts were identified with NucPlot41 and visual inspection of the cryo-EM reconstruction. Regions of the tRNA from the intron are indicated with the rectangle, representing the base, boxed in red. * indicates the TSEN34 catalytic residues which were all mutated to alanine to prevent cleavage. Interfaces between TSEN54 and c. and d. the acceptor stem e. the D-arm. f. Interface between the D-arm and TSEN2.