The 2 panels depict wild-type Abl in complex with STI-571 (imatinib; left) and predicted structure of STI-571 binding pocket of T315I mutant Abl in complex with STI-571 (right). In the molecular structures representing STI-571 and Abl residue 315, nitrogen atoms are shown in blue, and oxygen atoms are shown in red. A hydrogen bond between Thr315 (left) and STI-571 is shown by the dashed line. Van der Waals interactions are depicted in gray for STI-571 (both panels), in blue for wild-type Abl residue Thr315 (left), and in red for mutant Abl residue Ile315 (right). The polypeptide backbone of the Abl kinase domain is represented in green. Reprinted with permission from Science.