A certain ligand undergoes a conformational change in the binding pocket of a protein, but this change happens too rapidly to see it by X-ray crystallography. Instead, they used nuclear magnetic resonance spectroscopy (NMR) to capture this interesting behavior. In X-ray structures, the ligand always appears to be in the same conformation. The time scale of NMR enabled the authors to observe two different binding modes of the ligand, and show that the switching between these two binding modes happens in the binding site.