Thul R, Falcke M
Hahn-Meitner Institut, Abteilung Theorie, Glienicker Str. 100, D-14109 Berlin, Germany.
Phys Biol. 2005 Mar;2(1):51-9. doi: 10.1088/1478-3967/2/1/007.
We investigate the reaction dynamics of diffusive molecules with immobile binding partners. The fixed reactants build clusters that are comprised of just a few tens of molecules, which leads to small cluster sizes. These molecules participate in the reaction only if they are activated. The dynamics of activation is mapped to a time-dependent size of an active region within the cluster. We focus on the deterministic description of the dynamics of a single cluster. The spatial setup accounts for one of the most important determinants of the dynamics of a cluster, i.e. diffusional transport of reaction partners towards or away from the active region of the cluster. We provide numerical and analytical evidence that diffusion influences decisively the dynamic regimes of the reactions. The application of our methods to intracellular Ca2+ dynamics shows that large local concentrations saturate the Ca2+ feedback to the channel state control. It eliminates oscillations depending on this feedback.
我们研究了扩散性分子与固定结合伙伴之间的反应动力学。固定的反应物形成了仅由几十分子组成的簇,这导致簇的尺寸较小。这些分子只有在被激活时才参与反应。激活动力学被映射到簇内一个随时间变化的活性区域的大小。我们专注于单个簇动力学的确定性描述。空间设置考虑了簇动力学的最重要决定因素之一,即反应伙伴向簇的活性区域或远离该区域的扩散传输。我们提供了数值和分析证据,表明扩散对反应的动态机制有决定性影响。我们的方法应用于细胞内钙离子动力学表明,高局部浓度会使钙离子对通道状态控制的反馈饱和。它消除了依赖于这种反馈的振荡。