Salt-Excluding Artificial Water Channels Exhibiting Enhanced Dipolar Water and Proton Translocation

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• 作者：Erol Licsandru ; Istvan Kocsis ; Yue-xiao Shen ; Samuel Murail ; Yves-Marie Legrand ; Arie van der Lee ; Daniel Tsai ; Marc Baaden ; Manish Kumar ; Mihail Barboiu
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：April 27, 2016
• 年：2016
• 卷：138
• 期：16
• 页码：5403-5409
• 全文大小：499K
• 年卷期：0
• ISSN：1520-5126

文摘

Aquaporins (AQPs) are biological water channels known for fast water transport (∼10⁸–10⁹ molecules/s/channel) with ion exclusion. Few synthetic channels have been designed to mimic this high water permeability, and none reject ions at a significant level. Selective water translocation has previously been shown to depend on water-wires spanning the AQP pore that reverse their orientation, combined with correlated channel motions. No quantitative correlation between the dipolar orientation of the water-wires and their effects on water and proton translocation has been reported. Here, we use complementary X-ray structural data, bilayer transport experiments, and molecular dynamics (MD) simulations to gain key insights and quantify transport. We report artificial imidazole-quartet water channels with 2.6 Å pores, similar to AQP channels, that encapsulate oriented dipolar water-wires in a confined chiral conduit. These channels are able to transport ∼10⁶ water molecules/s, which is within 2 orders of magnitude of AQPs’ rates, and reject all ions except protons. The proton conductance is high (∼5 H⁺/s/channel) and approximately half that of the M2 proton channel at neutral pH. Chirality is a key feature influencing channel efficiency.