Structure of compound 2 in mode 1. (A) Cell-based, PathHunter IC50 values for compound 2 against TrkA, TrkB, and TrkC. (B) Zoom-in view of compound 2 binding. The central amide nitrogen is positioned to allow interactions with both carboxyl oxygens of Asp-668. Ile-490 sits above the indole, and as such, is referred to as mode 1.