Discovery of HG-7-85-01. (A) Chemical structure of HG-7-85-01 with substructure names indicated. (B) Kinase selectivity of HG-7-85-01 based on screening 400 kinases. Kinases where significant binding affinity was detected at 10μM were retested in dose-response format to determine a K_d. The size of the red circle is proportional to K_d. Numerical dissociation constants are listed in the supplemental Table. (C) X-ray crystal structure of the c-Src wt/HG-7-85-01 complex. HG-7-85-01 is shown in green carbon atoms, P-loop of the protein in red, helix α C in orange, and activation loop in blue. Dotted lines indicate H-bonds. (D) Accommodation of gatekeeper Thr315Ile mutation by HG-7-85-01 and AP24534. The kinase domains of the Src wt/HG-7-85-01 complex and the Abl Thr315Ile/AP24534 complex were aligned in PyMOL. The protein structures are highly conserved around the gatekeeper residues, and for clarity only the structure of Abl Thr 315, AP24534 (orange carbon atoms), and HG-7-85-01 (green carbon atoms) is displayed.