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1.D.176.  The Hydroxyl-rich Cholesterol-Flexible Alkyl Chain-Crown Ether  Ion Transporter (H-CIT-A-CE) Family 

The ion-fishing mechanism underlying ion transport across membranes mediated by an artificial ion transporter, composed of a hydroxyl-rich cholesterol group, a flexible alkyl chain, and a crown ether, have been investigated (Miao et al. 2022). The transporter can spontaneously insert into the membrane and switch between the folded (U-shaped) and extended (I-shaped) conformations. The free-energy profile associated with the conformational transition indicates that compared with the U-shaped conformation of the transporter, the I-shaped one is thermodynamically more favorable. The free-energy profiles describing ion translocation reveal the transporter capturing the ion in the U-shape on one side of the membrane and releasing it in the I-shape on the other side.  This constitutes a key way for the highly efficient transport of K+ ions. This presents a rigorous and rational framework to decipher the detailed ion-fishing mechanism of transmembrane ion transport with exceptionally high activity (Miao et al. 2022).

References associated with 1.D.176 family:

Miao, M., X. Shao, and W. Cai. (2022). Conformational Change from U- to I-Shape of Ion Transporters Facilitates K Transport across Lipid Bilayers. J Phys Chem B 126: 1520-1528. 35142530