Fig. 4

The “blocking” mechanism of ScADAT3. a The superimposition of the crystal structure of the yeast ScADAT3 PCD (yellow, PDB 7BV5), ScADAT2 CD (cyan, PDB 7BV5), and SaTadA (PDB 2B3J, magenta). The yellow and pink spheres represent the zinc ions in ScADAT3 PCD and SaTadA, respectively, and the ligands of the former are shown in sticks. Mini-tRNA is omitted for clarity. b Close-up of the zinc-binding site of ScADAT3. The distances between the zinc ion to the ligands are shown. c The steric clashes between the C-terminal loop of ScADAT3 and the hypothetical tRNA substrate. Coordinates of the RNA substrate (orange) are taken from the SaTadA-RNA complex (PDB 2B3J), and only the C32-A38 fragment is shown. For clarity, the U33-X34 bases of RNA are colored cyan, and the residues Asp317-Cys322 fragment is colored light blue. d The hydrophobic interactions formed by the C-terminal loop of ScADAT3. The hydrophobic interactions are shown by the magenta dashed lines