Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Chem Phys. 2021 Oct 28;155(16):164902. doi: 10.1063/5.0061376.
Recent experiments have suggested that enzymes and other small molecules chemotax toward their substrates. However, the physical forces driving this chemotaxis are currently debated. In this work, we consider a simple thermodynamic theory for molecular chemotaxis that is based on the McMillan-Mayer theory of dilute solutions and Schellman's theory for macromolecular binding. Even in the absence of direct interactions, the chemical binding equilibrium introduces a coupling term into the relevant free energy, which then reduces the chemical potential of both enzymes and their substrates. Assuming a local thermodynamic equilibrium, this binding contribution to the chemical potential generates an effective thermodynamic force that promotes chemotaxis by driving each solute toward its binding partner. Our numerical simulations demonstrate that, although small, this thermodynamic force is qualitatively consistent with several experimental studies. Thus, our study may provide additional insight into the role of the thermodynamic binding free energy for molecular chemotaxis.
最近的实验表明，酶和其他小分子会朝着它们的底物进行化学趋化运动。然而，目前对于驱动这种趋化运动的物理力存在争议。在这项工作中，我们考虑了一种基于稀溶液 McMillan-Mayer 理论和大分子结合 Schellman 理论的简单分子趋化热力学理论。即使没有直接相互作用，化学结合平衡也会在相关自由能中引入耦合项，从而降低酶及其底物的化学势。假设局部热力学平衡，这种化学势的结合贡献会产生一种有效的热力学力，通过将每个溶质推向其结合伙伴来促进趋化运动。我们的数值模拟表明，尽管很小，但这种热力学力与几项实验研究定性上是一致的。因此，我们的研究可能为分子趋化运动的热力学结合自由能的作用提供更多的见解。
