文章基本信息

标题：Implications for the impairment of the rapid channel closing of Proteomonas sulcata anion channelrhodopsin 1 at high Cl− concentrations
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作者：Takashi Tsukamoto ; Chihiro Kikuchi ; Hiromu Suzuki 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2018
卷号：8
期号：1
页码：13445
DOI：10.1038/s41598-018-31742-6
语种：English
出版社：Springer Nature
摘要：Natural anion channelrhodopsins (ACRs) have recently received increased attention because of their effectiveness in optogenetic manipulation for neuronal silencing. In this study, we focused on Proteomonas sulcata ACR1 ( Psu ACR1), which has rapid channel closing kinetics and a rapid recovery to the initial state of its anion channel function that is useful for rapid optogenetic control. To reveal the anion concentration dependency of the channel function, we investigated the photochemical properties of Psu ACR1 using spectroscopic techniques. Recombinant Psu ACR1 exhibited a Cl⁻ dependent spectral red-shift from 531 nm at 0.1 mM to 535 nm at 1000 mM, suggesting that it binds Cl⁻ in the initial state with a K _d of 5.5 mM. Flash-photolysis experiments revealed that the photocycle was significantly changed at high Cl⁻ concentrations, which led not only to suppression of the accumulation of the M-intermediate involved in the Cl⁻ non-conducting state but also to a drastic change in the equilibrium state of the other photo-intermediates. Because of this, the Cl⁻ conducting state is protracted by one order of magnitude, which implies an impairment of the rapid channel closing of Psu ACR1 in the presence of high concentrations of Cl⁻.