矢量离子传输的随机能量激发-弛豫通道模型的特性
Properties of the stochastic energization-relaxation channel model for vectorial ion transport.
作者信息
Muneyuki E, Fukami T A
机构信息
Research Laboratory of Resources Utilization, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
出版信息
Biophys J. 2000 Mar;78(3):1166-75. doi: 10.1016/S0006-3495(00)76674-4.
A model for the primary active transport by an ion pump protein is proposed. The model, the "energization-relaxation channel model," describes an ion pump as a multiion channel that undergoes stochastic transitions between two conformational states by external energy supply. When the potential profile along ion transport pathway is asymmetrical, a net ion flux is induced by the transitions. In this model, the coupling of the conformational change and ion transport is stochastic and loose. The model qualitatively reproduces known properties of active transport such as the effect of ion concentration gradient and membrane potential on the rate of transport and the inhibition of ion transport at high ion concentration. We further examined the effect of various parameters on the ion transport properties of this model. The efficiency of the coupling was almost 100% under some conditions.
提出了一种离子泵蛋白介导的原发性主动转运模型。该模型即“能量激发-松弛通道模型”，将离子泵描述为一个多离子通道，其通过外部能量供应在两种构象状态之间进行随机转变。当沿离子传输途径的电位分布不对称时，这些转变会诱导净离子通量。在该模型中，构象变化与离子传输的耦合是随机且松散的。该模型定性地再现了主动转运的已知特性，如离子浓度梯度和膜电位对转运速率的影响以及高离子浓度下对离子转运的抑制。我们进一步研究了各种参数对该模型离子传输特性的影响。在某些条件下，耦合效率几乎达到100%。
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