Ribbon representation of ABL in complex with imatinib and ID180970. Shown is (A) the conformation of Abl (blue) in complex with imatinib (orange), with the A-loop (magenta) in a “closed” conformation, and (B) the Abl conformation (green) in the PD180970 (red) complex with the A-loop (magenta) in an “open” conformation. The P-loop (yellow) folds down over the inhibitor in both cases. Figure prepared by Sandra W. Cowan-Jacob based on reported structures.^85,88