Liebovitch L S, Selector L Y, Kline R P
Department of Ophthalmology, College of Physicians & Surgeons, Columbia University, New York, New York 10032.
Biophys J. 1992 Dec;63(6):1579-85. doi: 10.1016/S0006-3495(92)81732-0.
It has been proposed that part of a voltage gated channel is a tethered ball and that inactivation occurs when this wandering ball binds to a site in the channel. In order to be able to quantitatively test this model by comparison to experiments we developed analytical solutions and numerical simulations of the distribution of times it takes the ball to reach the binding site when the motion of the ball is random and when it is also influenced by a directed force. If the motion of the ball is one-dimensional, at long times this distribution is a single exponential with a rate constant that is inversely proportional to the square of the length of the chain and does not depend on the starting position of the ball. This dependence on the chain length is not significantly altered if there are short range electrical forces between the ball and its binding site. These predictions suggest that to confirm the validity of this model additional experiments should be done to more precisely determine the form of this distribution and its dependence on the length of the chain.
有人提出，电压门控通道的一部分是一个系留球，当这个游动的球与通道中的一个位点结合时，就会发生失活。为了能够通过与实验比较来定量测试这个模型，我们针对球的运动是随机的以及球的运动还受定向力影响这两种情况，开发了球到达结合位点所需时间分布的解析解和数值模拟。如果球的运动是一维的，在长时间情况下，这种分布是一个单指数分布，其速率常数与链长度的平方成反比，并且不依赖于球的起始位置。如果球与其结合位点之间存在短程电力，这种对链长度的依赖性不会有显著改变。这些预测表明，为了证实这个模型的有效性，应该进行更多实验，以更精确地确定这种分布的形式及其对链长度的依赖性。
