运用单通道实验数据和仿真数据比较马尔可夫模型和分形模型

Compared Markov with Fractal Models by Using Single-channel Experimental and Simulation Data

离子通道门控机制动力学的研究广泛地运用马尔可夫模型去讨论。马尔可夫模型假设离子通道动力学只含有少数几个离散的构象状态,并且状态之间的转移速率是常数、它不依赖于时间和先前的状态过程。L iebov itch和他的同事提出了运用分形模型去刻划离子通道门控机制动力学,他们认为:离子通道门控机制动力学具有连续的构象状态,状态之间的转移速率依赖于时间并且为时间t的函数。现在的焦点在于离子通道门控机制动力学马尔可夫模型或分形模型是否恰当地描述了其通道门控的分子事件,是否合理地解释其生理机理。在本研究中,我们采用实验记录的离子单通道数据和随机仿真的数据来比较马尔可夫模型和分形模型,实验记录的离子单通道数据来源于电压依赖性的钾离子单通道,随机仿真的数据来源于三个状态的马尔可夫模型。

The gating mechanical kinetical of ion channels has been modeled as a Markov process. In these models it is assumed that the channel protein has a small number of discrete conformational states and kinetic rate constants connecting these states are constant, the transition rate constants among the states is independent both of time and of the previous channel activity. It is assumed in Liebovitch＇s fractal model that the channel exists in an infinite number of energy states, consequently, transitions from one conductance state to another would be governed by a continuum of rate constants. In this paper, a statistical comparison is presented of Markov and fractal models of ion channel gating, the analysis is based on slngle-channel data from ion channel voltagedependence K^＋ single channel of neuron cell and simulation data from three-states Markov model.