随机门控作为一种新型的通道选择性机制。
Stochastic Gating as a Novel Mechanism for Channel Selectivity.
机构信息
Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Mathematical and Statistical Computing Laboratory, Division for Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland.
Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland.
出版信息
Biophys J. 2018 Mar 13;114(5):1026-1029. doi: 10.1016/j.bpj.2018.01.007. Epub 2018 Feb 12.
An ideal channel, responsible for metabolite fluxes in and out of the cells and cellular compartments, is supposed to be selective for a particular set of molecules only. However, such a channel has to be wide enough to accommodate relatively large metabolites, and, therefore, it allows passage of smaller solutes, for example, sodium, potassium, and chloride ions, thus compromising membrane's barrier function. Here we show that stochastic gating is able to provide a mechanism for the selectivity of wide channels in favor of large metabolites. Specifically, applying our recent theory of the stochastic gating effect on channel-facilitated transport, we demonstrate that under certain conditions gating hinders translocation of fast-diffusing small solutes to a significantly higher degree than that of large solutes that diffuse much slower. We hypothesize that this can be used by Nature to minimize the shunting effect of wide channels with respect to small solutes.
一种理想的通道，负责细胞和细胞区室内外代谢物的通量，应该只对特定的分子集合具有选择性。然而，这样的通道必须足够宽以容纳相对较大的代谢物，因此，它允许较小的溶质通过，例如钠、钾和氯离子，从而损害膜的屏障功能。在这里，我们表明随机门控能够为宽通道对大代谢物的选择性提供一种机制。具体来说，应用我们最近关于随机门控效应对通道促进运输的理论，我们证明在某些条件下，门控对快速扩散的小分子的转运阻碍程度要比扩散速度慢得多的大分子高得多。我们假设，大自然可以利用这一点来最小化宽通道对小分子的分流效应。
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