Development of second-generation menin-MLL inhibitors. (A) Structures and activities of new compounds designed based on the structure of the menin–MI-2 complex. IC50 values for the inhibition of the menin-MBM1 complex are provided in parentheses. (B) FP experiments comparing activities of MI-2, MI-2-2 and MBM1 for disruption of the menin-MBM1 interaction demonstrating that MI-2-2 is a more potent inhibitor than an MLL-derived peptide. (C) Isothermal titration calorimetry showing the binding of MI-2-2 to menin. N represents a stoichiometry of binding. (D) Crystal structure of the menin–MI-2-2 complex determined at 1.27 Å resolution with corresponding 2Fo-Fc electron density map contoured at 1σ level. Water molecules were omitted for clarity. (E) Orthogonal dipolar interactions between MI-2-2 fluorine and backbone atoms of His181. The distances are shown in Å.
