A Small Molecule Agonist of EphA2 Receptor Tyrosine Kinase Inhibits Tumor Cell Migration In Vitro and Prostate Cancer Metastasis In Vivo
Figure 3
Structure and dynamics of the EphA4-doxazosin complex.
(A) 1H-15N NMR HSQC spectra of the EphA4 LBD in the absence (blue) and in the presence (red) of doxazosin (DZ) at a molar ratio of 1∶5 (EphA4∶DZ). Several residues located over the convex surface of the EphA4 ephrin-binding channel are labeled. (B) Residue-specific chemical shift index (CSI) of the EphA4 LBD in the presence of doxazosin at a molar ratio of 1∶5 (EphA4∶DZ). Significantly-shifted residues shared with C1 are colored in bright brown, while the residues significantly shifted only by doxazosin binding are in red. (C) The docking model of the EphA4-doxazosin complex in ribbon. Binding regions identical to those for the C1-binding were colored in brown, while those unique for the doxazosin binding in red. G, K, M and E are used to donate β-strands of the convex surface of EphA4/ephrin-binding channel. (D) EphA4 residues having direct contacts with doxazosin. Residues on D–E and J–K loops are in brown, those on the convex surface in violet, and Arg106 in cyan. Green dashed lines indicate hydrogen bonds between doxazosin and EphA4 residues. (E)–(F) The same docking model with the electrostatic potential of the EphA4 LBD displayed. (G) EphA4 LBD in free and doxazosin-bound states display different squared generalized order parameter S2 (Figure S6A). Blue: S2 difference ≤−0.01; red: S2 difference ≥0.01; brown: no significant change or S2 values not determined. (H) Conformational exchanges of EphA4 in free (left panel) and doxazosin-bound states (right panel). Residues with Rex>5 (Figure S6B) are displayed in balls and colored in red. (I) A docking model of the EphA2-doxazosin complex. Contact residues in D–E and J–K loops are labeled in brown, on the convex surface in cyan, and Arg103 in violet. The violet dash is used to indicate the hydrogen bonds between doxazosin and EphA2 residues.