Albaugh Alex, Gu Geyao, Gingrich Todd R
Department of Chemistry, Northwestern University, Evanston, IL 60208.
Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202.
Proc Natl Acad Sci U S A. 2023 Aug 15;120(33):e2210500120. doi: 10.1073/pnas.2210500120. Epub 2023 Aug 7.
Simulations can help unravel the complicated ways in which molecular structure determines function. Here, we use molecular simulations to show how slight alterations of a molecular motor's structure can cause the motor's typical dynamical behavior to reverse directions. Inspired by autonomous synthetic catenane motors, we study the molecular dynamics of a minimal motor model, consisting of a shuttling ring that moves along a track containing interspersed binding sites and catalytic sites. The binding sites attract the shuttling ring while the catalytic sites speed up a reaction between molecular species, which can be thought of as fuel and waste. When that fuel and waste are held in nonequilibrium steady-state concentrations, the free energy from the reaction drives directed motion of the shuttling ring along the track. Using this model and nonequilibrium molecular dynamics, we show that the shuttling ring's direction can be reversed by simply adjusting the spacing between binding and catalytic sites on the track. We present a steric mechanism behind the current reversal, supported by kinetic measurements from the simulations. These results demonstrate how molecular simulation can guide future development of artificial molecular motors.
模拟有助于揭示分子结构决定功能的复杂方式。在此，我们使用分子模拟来展示分子马达结构的微小改变如何导致马达典型的动力学行为发生方向逆转。受自主合成索烃马达的启发，我们研究了一个最小马达模型的分子动力学，该模型由一个穿梭环组成，它沿着包含散布的结合位点和催化位点的轨道移动。结合位点吸引穿梭环，而催化位点加速分子物种之间的反应，这些分子物种可被视为燃料和废物。当燃料和废物保持在非平衡稳态浓度时，反应产生的自由能驱动穿梭环沿轨道定向运动。使用这个模型和非平衡分子动力学，我们表明，只需调整轨道上结合位点和催化位点之间的间距，穿梭环的方向就可以逆转。我们提出了电流逆转背后的空间位阻机制，并得到了模拟动力学测量的支持。这些结果证明了分子模拟如何能够指导人造分子马达的未来发展。
