1.D.220.  The AminoCycloDextrin Ion Channel (ACD-IC) Family 

Gin and co-workers reported an aminocyclodextrin ion channel (15) that showed pH dependence due to the appended amino groups (see Fig below) (Madhavan and Gin 2007).  The rate of cation transport as well as anion transport increased at a pH of 8 and above. The electrostatics of the cavity plays an important role in dictating ion transport rates. At low pH, the protonated amines strongly repel cations and attract anions. The strong anion complexation inhibits anion transport (Kumar and Madhavan 2023).

pH-dependence of ion transport driven by electrostatic interactions with aminocyclodextrins, 15.



Kumar, N. and N. Madhavan. (2023). Small molecule-derived pH-gated ion transporters. Org Biomol Chem. [Epub: Ahead of Print]

Madhavan, N. and M.S. Gin. (2007). Increasing pH causes faster anion-and cation-transport rates through a synthetic ion channel. Chembiochem 8: 1834-1840.

Zheng, S.P., J.J. Jiang, A. van der Lee, and M. Barboiu. (2020). A Voltage-Responsive Synthetic Cl -Channel Regulated by pH. Angew Chem Int Ed Engl 59: 18920-18926.