Allostery in Guest Binding of Rim‐to‐Rim‐Connected Homoditopic Biscavitands. Issue 20 (19th June 2016) - Shimoyama, Daisuke
Abstract : Rim‐to‐rim‐connected phosphonate biscavitands1a and1b were synthesized. Crystal structure analysis and variable‐temperature NMR spectroscopy studies reveal that1a is more rigid in conformation than1b . Biscavitands1a and1b bind cationic guestsG1 –G3 through hydrogen bonding and CH–π interactions, demonstrating positive and negative allosteric effects, respectively. The allosteric effects in guest binding are associated with the conformational flexibilities of1a and1b . The positive allosteric effect of1a is directed by the tightly connected cavities, in which information of the first guest binding is transferred to the remaining cavity, which becomes preorganized. In contrast, a slightly negative allosteric effect is found in more‐flexible1b . Abstract : Rim‐to‐rim‐connected phosphonate biscavitands are synthesized. Positive homotropic allostery in guest (G) binding is observed. The allosteric regulation is determined by the structural flexibility of four linkages, which bridge two binding sites.