Folding and Unfolding of a Fully Synthetic Transmembrane Receptor for ON/OFF Signal Transduction.

Signal transduction processes in living organisms are mainly transmitted through conformational changes in transmembrane protein receptors. So far, the development of signal transduction models induced by artificial simulation of conformational changes remains limited. We herein report a new artificial receptor that achieves controllable "ON/OFF" signal transduction through conformational changes between the folding and unfolding of a transmembrane foldamer moiety. The receptor contains three functional modules: a lipid-anchored cholic acid headgroup, a foldamer transmembrane moiety, and a precatalyst tailgroup. After inserting in the lipid membrane, the addition of Zn 2+ induces unfolding of the foldamer, which changes the molecular conformation and activates the tailgroup to enter the cavity to perform its catalytic task, resulting in signal transduction in an "ON" state. By further adding a competitive ligand to bind Zn 2+ , the transduction can be turned "OFF". External signals can be used to reversibly switch intravesicular catalysis on and off, which provides a new model for constructing artificial signal transduction systems.