分子马达定向运动机制的研究

【作者】 田茎；

【导师】 李玉晓；

【作者基本信息】 郑州大学 ， 粒子物理与原子核物理， 2007， 硕士

【摘要】 分子马达是具有马达功能的蛋白质大分子，广泛存在于生物体细胞内，是一类可以高效率的将储存在ATP中的化学能直接转化为机械能的蛋白质。生物体的一切生命活动，都离不开分子马达做功的推动。分子马达通过催化ATP水解获得能量，从而产生宏观运动，在这个过程中，伴随着ATP水解的化学过程而产生的运动的动力学机制是我们关注的焦点问题。由于在分子尺度上，蛋白质马达布朗运动的特征十分明显，因而在不考虑分子马达构象变化的情况下，通常把分子马达抽象为布朗粒子，利用非平衡态统计理论解释分子马达在介质中的运动机制。周围环境的影响被简化为某种特定形式噪声的激励作用，分子马达与轨道之间的相互作用可以用特定的势函数来表示。论文中首先简单地介绍了几种经典的马达蛋白的生物结构和催化ATP水解的工作机制；接着，介绍在描述分子马达定向运动机制中常用的主方程和Langevin方程，详细介绍了数值求解Langevin方程的Runge-Kutta算法和Monte Carlo模拟方法，并结合简单具体模型进行了讨论。在第三部分，介绍了一些特殊的布朗马达模型。第四章中我们提出了二维闪烁布朗马达型，分析了在白噪声作用下和非恒定外部驱动力下的分子马达各个参量的对稳态流J的影响。更多还原

【Abstract】 Molecular motors are cellular proteins able of converting chemical energy of ATP into mechanical force with high efficiency. Most of the life activities depend on the motor protein and mechanical work it does. The energy source of the cell is hydrolization of ATP, thereby generating directional motion. In this procedure, molecular dynamical mechanics which adjoint with hydrolization of ATP received extensive interests.In the scale of molecule, the movement of the proteins has the features of Brownian movement. So we can take molecular motor as a Brownian particle in the case of ignoring the conformational changes. We can use nonequilibrium statistical theory to explain the working mechanics of molecular motor in the realm of physics. The effect of the environment can be simplified as a noise while the interactions between molecular motor and its tracks can be described by a special potential.At first, in the thesis of ours, the structures of several kinds of well known motors and their cycle of ATP hydrolization were introduced briefly. Secondly, we give out the Master Equation and Langevin Equation which were commonly used to explain the work mechanics of molecular motor. Then we discussed two numerical methods to solve stochastic differential equation: Runge-Kutta algorithms and Monte Carlo Simulations, with these we give out a simple example to display how to use them. In part three, we introduce some special model of molecular motors. Finally, we give out the two dimensions flashing potential model under white noise, we analysis the current behaviors under different environment variables.更多还原