Only the part of the tunnel in the S1 domain was considered in the CaverDock calculations. We discretised the tunnel into a set of discs using the program's default settings. The ligand and receptor files were prepared using MGLtools 1.5.7. The grid box was generated around the relevant part of the tunnel using a script from the CaverDock package. The default drag atom (i.e. the atom closest to the centroid of the molecule) was used. Calculations were run in the inward direction only, in the lower-bound trajectory mode.