Crystal structure of the NUDT15 TH7755 complex.A, crystallographic structure of dimeric NUDT15. Individual monomers are shown as ribbon representations, colored cyan and green. The TH7755 ligands are depicted as stick models; C atoms are colored yellow, O atoms red, N atoms blue, and S atoms gold. B, ribbon representation of the NUDT15 monomer in complex with TH7755. The secondary structure elements, alpha-helices (α1-2), beta-strands (β1-7), and 310-helices (η1-4) are labeled. C, hydrogen bond network for TH7755 in the NUDT15 active site. Amino acids involved in ligand coordination are depicted as sticks. Important water molecules are shown as red spheres. Hydrogen bond interactions are shown as dashed lines. The 2Fo − Fc electron density map around TH7755 is contoured at 1.5 σ, and the Fo − Fc electron density map is contoured at 3.0 σ. D, comparison of NUDT15–TH7755 (cyan) with NUDT15 in complex with TH1760 (white, PDB ID: 6T5J). TH1760 is depicted as a stick model; C atoms are colored magenta, O atoms red, N atoms blue, and S atoms gold.