Figure 4

Interactions of imatinib with NQO2. A) Schematic of imatinib-NQO2 interactions. Van der Waals interactions of imatinib with NQO2 residues are indicated as semi-circles, and hydrogen bonds are represented by dotted lines. Contacts from each NQO2 monomer are colored green or orange. B) Residues involved in contacts between imatinib and NQO2 are primarily hydrophobic interactions. One water-mediated hydrogen bond is formed between imatinib and the side chain of Asn 161, which is positioned by a hydrogen-bonding interaction with Tyr 132. Residues involved in contacts between imatinib and NQO2 are shown as stick figures, and water molecules are shown as red spheres. Not shown: Gly 149, Gly 150, Thr 151, and Ile 194. C) Surface representation of the active site of NQO2 in complex with the kinase inhibitor imatinib. In each panel, the FAD and imatinib molecules are depicted as yellow and blue stick figures, respectively; nitrogen is colored blue and oxygen, red. Water molecules are shown as red spheres. The imatinib rings are lettered as in Figure 1A.