Receptor grid generation and docking. Grid generation for SurA used the frame with the most druggable and consistently identified site as described above (kindly provided by T. Kronenberger), and the receptor grid with a size of 30 Å 3 was centered on the site centroid. For GAK, the grid center was defined as the centroid of the crystallographic ligand. Both grids were prepared with the OPLS_2005 forcefield. For GAK, additionally, a hydrogen-bonding constraint on the hinge-region amide (Cys126 backbone amide hydrogen) was set up.