The Synthetic Chloride Membrane Transporter (SCMTR) Family

Synthetic chloride membrane transporter (SCMTR) 65b, introduced in 2002, was the first synthetic anion channel (Schlesinger et al. 2002). Minooei et al. 2018 investigated the role of the N-terminal chain and linker units on the single channel activity of SCMTR analogues (see figure below). Conductance measurements were made using planar bilayers made from 3 different lipids: (1) asolectin, (2) DOPC:egg PE and (3) DPhPC. The most active chloride-selective channel, made from SCMTR 65a, had two unique conductance states in membranes made from asolectin (15.5 ± 4.1 pS and 27.8 ± 3.1 pS at 65 mV) and from DOPC: egg PE (18.8 ± 1.6 and 20.3 ± 1.9 pS at −130 mV). Notably, 65a did not form channels in membranes made from DPhPC, a popular lipid in the channel field. These results showed that ion transporters, particularly those that self-assemble to form channels, interact differently with various lipids. MD simulations revealed membrane reorganization during formation of SCMTR channels. 

Structures of SCMTR 65a and SCMTR 65b, which gave the first example of a synthetic anion channel. The two analogues differ in their N-terminal aliphatic chains (C12vs. C18) and in their linker regions (succinic vs. glycolic acid).




Minooei, F., , M.D. Martin, , J.R. Fried, , and J.P. Brian,. (2018). Electrophysiological measurements reveal that a succinyl linker enhances performance of the synthetic chloride channel SCMTR. Chem Commun (Camb) 54: 4689-4691.

Schlesinger, P.H., R. Ferdani, J. Liu, J. Pajewska, R. Pajewski, M. Saito, H. Shabany, and G.W. Gokel. (2002). SCMTR: a chloride-selective, membrane-anchored peptide channel that exhibits voltage gating. J. Am. Chem. Soc. 124: 1848-1849.