Department of Physics, University of Pavia, I-27100, Pavia, Italy.
Institute of Quantitative and Theoretical Biology, Heinrich Heine University, 40225, Düsseldorf, Germany.
Sci Rep. 2019 Nov 13;9(1):16657. doi: 10.1038/s41598-019-52842-x.
The Q-cycle mechanism entering the electron and proton transport chain in oxygenic photosynthesis is an example of how biological processes can be efficiently investigated with elementary microscopic models. Here we address the problem of energy transport across the cellular membrane from an open quantum system theoretical perspective. We model the cytochrome [Formula: see text] protein complex under cyclic electron flow conditions starting from a simplified kinetic model, which is hereby revisited in terms of a Markovian quantum master equation formulation and spin-boson Hamiltonian treatment. We apply this model to theoretically demonstrate an optimal thermodynamic efficiency of the Q-cycle around ambient and physiologically relevant temperature conditions. Furthermore, we determine the quantum yield of this complex biochemical process after setting the electrochemical potentials to values well established in the literature. The present work suggests that the theory of quantum open systems can successfully push forward our theoretical understanding of complex biological systems working close to the quantum/classical boundary.
在含氧光合作用中，进入电子和质子传输链的 Q 循环机制是一个如何使用基本微观模型有效地研究生物过程的例子。在这里，我们从开放量子系统理论的角度来解决细胞膜能量传输的问题。我们从一个简化的动力学模型出发，对细胞色素 [Formula: see text] 蛋白复合物在循环电子流条件下的情况进行建模，在此基础上，我们重新采用了马尔可夫量子主方程公式和自旋-玻色子哈密顿处理方法。我们应用这个模型从理论上证明了在环境和生理相关温度条件下，Q 循环的最佳热力学效率。此外，我们在将电化学势设定为文献中已确立的值后，确定了这个复杂生化过程的量子产率。本工作表明，量子开放系统理论可以成功地推动我们对接近量子/经典边界的复杂生物系统的理论理解。
