Nonprotonophoric Electrogenic Cl− Transport Mediated by Valinomycin-like Carriers

Abstract

Synthetic anion transporters can facilitate H + transport via deprotonation, or OH À transport via hydrogen bonding to OH À , thus allowing dissipation of transmembrane pH gradients, an undesired side-effect for biomedical applications as Cl À ionophores. To address this limitation, Gale and colleagues have developed two anionophores that show high Cl À > H + /OH À selectivity. Preliminary cellular studies support the biological relevance of the selectivity.

A synthetic ion transporter that disrupts autophagy and induces apoptosis by perturbing cellular chloride concentrations

“…During electroneutral processes, no net transfer of charge occurs and the transport of the two ions (one cation and one anion, or two different anions) cannot be separated. Using a recently developed method 32,33 , and exploiting both valinomycin (an electrogenic K + transporter) 34 and monensin (an electroneutral M + /H + transporter) 35 , we conclude that 3 is capable of both electrogenic Cl − transport and electroneutral H + /Cl − (OH − /Cl − ) transport (Fig. 2c,d).…”

New Insights into the Anion Transport Selectivity and Mechanism of Tren‐based Tris‐(thio)ureas

“…[12] These two assays have been used extensivelyt o probe the potentialo fmany different classes of compounds to facilitateanion transport. [15] Herein, we report acomprehensive study of aseries of previously reported tren-based compounds [16] using new assays that measure anion uniport and hence can be used to determine selectivity of transport. The requirement that transport of the anion of interesti st he rate-limitingt ransport step led to the use of lipophilic nitrate as the external anion.R ecently it was shown that chloride transport ability was underestimated for trenbased anionophores in these exchange assays, as anion exchange was rate limited by nitrate transport.…”

A folding decalin tetra-urea for transmembrane anion transport

“…Surrounding the target anion had been found to increase transport activities 16 as well as to moderate selectivities. 17 Here we report the synthesis of tetra-urea 7, structural and binding studies, and preliminary transport experiments. We find that 7 can be organised to create an effective chloride binding site, and is active as both receptor and transporter.…”