A simplified model for V-ATPase H+ extrusion
A simplified model for V-ATPase H+ extrusion
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DOI：
10.1109/tnb.2004.837905
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发表时间：
2004-12-01
影响因子：
3.9
通讯作者：
Bidani, A
中科院分区：
文献类型：
--
作者：
Luo, C;Clark, JW;Bidani, A
V型H+易位ATP酶（V-ATP酶）的分析模型是基于Grabe等人的机械化学模型的近似（Biophys. J.，pp. 2798-2813，第78卷，2000）。Grabe的工作利用结构信息和生理假设来构建V-ATPase的详细机械化学模型。由于他们的模型的复杂性，它没有给出一个容易使用的数学表达式的V-ATP酶电流。基于他们对质子泵结构的分析，我们开发了V-ATPase的二室模型，该模型包含用于质子转运的膜“半通道”，其由亲水性条带和疏水性壁与细胞质分离。使用朗之万方程来描述质子跨膜传输，我们简化了模型的基础上，他们的假设上的分子结构的泵和到达的一般形式的解决方案的质子泵流量驱动的ATP水解的基础上的假设的生理特性的带和壁，以及两个流体隔室。在这个简化的过程中，我们明确地涉及V-ATP酶的结构，化学计量，泵效率，和ATP水解能量的活性泵电流。简化模型用于提供模型生成的近似值，以测量来自各种实验室的数据。此外，它提供了一个非常紧凑的V-ATP酶的表征，它可以用作质子挤出机在各种不同的细胞膜，以及在细胞内细胞器的膜。
An analytical model of V-type H+-translocating ATPase (V-ATPase) was developed based on an approximation to the mechanochemical model of Grabe et al. (Biophys. J., pp. 2798-2813, vol. 78, 2000). Grabe's work utilizes structural information and physiological assumptions to construct a detailed mechanochemical model of the V-ATPase. Due to the complexity of their model, it does not give a readily usable mathematical expression for the V-ATPase current. Based on their analysis of the structure of the proton pump, we develop a two-compartment model of the V-ATPase, which contains a membrane "half-channel" for proton translocation separated by a hydrophilic strip and a hydrophobic wall from the cytoplasm. Using the Langevin equation to describe proton transport across the membrane, we simplify the model based on their assumptions on the molecular structure of the pump and arrive at a general form of solution to the proton pump flux driven by ATP hydrolysis based on assumptions on the physiological properties of the strip and the wall, as well as the two fluid compartments. In this process of simplification, we explicitly relate V-ATPase structure, stoichiometry, pump efficiency, and ATP hydrolysis energy to the active pump current. The simplified model is used to provide model-generated approximations to measured data from a variety of laboratories. In addition, it provides a very compact characterization of V-ATPase, which can be used as a proton extruder in a variety of different cell membranes, as well as in the membranes of intracellular organelles.