Diffusion and residence time of hydrogen peroxide and water in crowded protein environments
Diffusion and residence time of hydrogen peroxide and water in crowded protein environments
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DOI：
10.1021/jp075251
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发表时间：
2007-11-22
影响因子：
3.3
通讯作者：
Margulis, Claudio J.
中科院分区：
文献类型：
--
作者：
Chung, Ying-Hua;Xia, Junchao;Margulis, Claudio J.
活性氧（ROS）在细胞信号传导中具有重要作用，当活性氧水平过高时，可能导致重要生物分子的氧化。研究线粒体内ROS扩散的动力学模型通常假设与溶液中的动力学相似。然而，众所周知，在细胞质或线粒体内（ROS占主导地位），蛋白质的分离可以小于1nm。小分子的扩散可以更好地看作是一个渗透过程。在本文中，我们报告了水和过氧化氢在蛋白质附近的扩散率和驻留的结果。在进行这项研究时，我们发现传统的使用生存时间相关函数计算停留时间的方法存在一些问题。主要问题是，长时间停留在蛋白质表面的颗粒，其统计数据非常差，对存活时间相关函数的短时间行为有重大影响。我们用数学方法描述了这个问题，并提出了克服它的方法。
Reactive oxygen species (ROS) have important functions in cell signaling and, when present at overly high levels, may cause oxidation of important biological molecules. Kinetic models to study diffusion of ROS inside of mitochondria often assume dynamics similar to that in solution. However, it is well-known that separation of proteins in the cytosol or inside of mitochondria, where ROS are most predominant, can be smaller than 1 nm. Diffusion of small molecules can be better regarded as a percolation process. In this article, we report results of diffusivity and residence of water and hydrogen peroxide in the proximity of proteins. In carrying out this study, we found some issues with the conventional way of computing residence times by means of survival time correlation functions. The main problem is that particles remaining on the surface of a protein for long times and for which one has very poor statistics contribute significantly to the short time behavior of the survival time correlation function. We mathematically describe this problem and propose methodology to overcome it.