Allosteric binding of sodium deoxycholate by a bis(β-cyclodextrin)-2,2′-bipyridine receptor

The synthesis of a new positively allosteric bis(β-cyclodextrin) receptor 1 is described. The binding affinity of the receptor in its “on” and “off” states towards sodium deoxycholate in aqueous solution was studied by means of isothermal titration calorimetry and NMR spectroscopic titrations. The allosteric effect amounts to a more than 18-fold increase of the binding constant of receptor 1 towards the substrate upon addition of a zinc(II) phenanthroline complex that acts as an effector for the allosteric 2,2′-bipyridine motif.