Fig. 4: Crystal structure for naltrexone-bound Variant 3A7.
From: Highly multiplexed design of an allosteric transcription factor to sense new ligands
a Binding pocket of Variant 3A7 with naltrexone. Gray molecule is naltrexone. Green side chains indicate mutant positions. Pink side chains indicate positions within 4 Å of the naltrexone molecule. b Three instances of Met-Aro interactions within the binding pocket, mediated by the mutant residues. WT TtgR (PDB: 7K1C) is shown in gray and 3A7 is shown in light purple. Green side chains indicate mutant positions. Naltrexone is shown in pink. Molecular distances for each interaction are indicated. c Ligand entry port of WT TtgR (gray) and Variant 3A7 (light purple). Darkened surface residues denote positions of C137 and R75. Dotted red lines indicate rotation angles of C137 and R75 in WT (dark gray) TtgR and Variant 3A7 (dark purple). Green side chains indicate mutant positions.
