水溶性人工レセプターの設計と分子認識のメカニズム

Abstract

Development of water-soluble synthetic receptors is described, particularly focusing on the mechanistic aspects of binding. Binding of guest by receptor is driven by (1) enthalpic stabilization owing to the host-guest attractive forces and (2) entropic stabilization upon desolvation. A number of thermodynamic data collected for synthetic receptors indicate that the binding in organic solvent is enthalpically driven while that in water both entropically and enthalpically driven. The average binding constant of cyclodextrins is 102.4M-1, while that of proteins 109.3M-1, indicating that understanding of the large difference in affinity between synthetic and native receptors will help further development of synthetic receptor chemistry. One important aspect of biological recognition is the switching between the R state and the T state of the receptor as suggested by the induced-fit binding model. Design of the receptor with a conformationally or solvationally unstable state will be the key to the higher-order functions of the synthetic receptors. The important role of synthetic organic chemistry in the development of these functional molecules is emphasized.