Fig. 1: Possible working principle of potassium ion transporters.

a, b illustrate molecular design and structures of hosts h and H as well as guest molecules 1–3. c A schematic illustration of how an azo-benzene-derived molecular ion transporter might become controllable in the presence of lipid anchor-modified β-CD molecule through photoresponsive host-guest recognition. Note that step 5 can take place anywhere in the membrane. Based on the computed binding energies presented in Supplementary Fig. 15, the released cis-form likely binds K⁺ to generate an intramolecular cyclic complex for facilitating K⁺ transport.