Article Title: Ligand promiscuity in the tryptophan repressor – from structural understanding towards rational design
Figure Lengend Snippet: Diverse ligand binding in TrpR. (A) Ligands studied. (B) Structure of TrpR with helices labeled by letters. (C–G) TrpR bound to the native ligand TRP, the co-repressors 5-methyl-tryptophan and 5-methyl-tryptamine, and the pseudo-repressors IPA and IAA. (H) Binding pocket colored by rmsd of the former five structures (red = high, blue = low). (I–J) TrpR-S88Y with IAA and IPA. Shown are magnifications as indicated in (B). Ligand 2F O -F C density is contoured at 1σ. Important interactions are indicated by red dashed lines (electrostatic) and spheres (van-der-Waals).
Article Snippet: Ligands 5-methyl-tryptophan (order no. M0534), 5-methyl-tryptamine (order no. 134228), indole-3-acetic acid (order no. i2886), indole-3-propionic acid (order no. 57400) and indole-3-butyric acid (order no. i5386) have been obtained from Sigma-Aldrich.
Techniques: Ligand Binding Assay, Labeling, Indirect Immunoperoxidase Assay, Binding Assay