Entropic tunneling time sheds light on efficient potassium ion transition in KcsA channel

Official URL: https://dx.doi.org/10.1016/j.pbiomolbio.2026.03.002

Biological systems continuously interact with their environment, exchanging energy and matter to preserve the non-equilibrium state that is fundamental to life. Quantum effects, including tunneling, have been increasingly recognized as contributing to complex biological behaviors, making ion channels a particularly intriguing subject due to their rapid and selective conduction properties. Here, we investigate the mechanisms underlying K+ ion transport through the KcsA channel, incorporating thermal averaging at physiological temperature (300 K) to estimate the delay time across barrier regions. Utilizing recent advancements in molecular dynamics simulations and quantum tunneling time calculations, this paper examines ion tunneling processes and their temporal aspects using quantum-classical hybrid methods, revealing that a single K+ ion spends approximately 5 ns within the channel's selectivity filter, consistent with biologically observed timescales and experimental measurements. These findings suggest that classical models alone may inadequately capture ion transport dynamics and emphasize the significance of quantum effects under physiological conditions. The study highlights the importance of integrating quantum biological perspectives to deepen our understanding of complex physiological processes.