Lateral Transport of Protons along Thin Layers of Water on the Surface of Biomembranes

One of the current directions in cell bioenergetics is a study of the molecular mechanisms underlying effective proton transport in proteins and surface proton-conducting structures along biomembranes. In this paper, we developed a mathematical model of lateral proton transport along a water-membrane interface. We considered a model of the proton movement in quasi 1D lipid domain structures in multicomponent lipid membranes, which are proposed to play proton-conducting lateral structures. The developed approach is based on a model of the three-component system including the subsystem of hydrogen bonded chains of surface water molecules interacting with the polar groups and hydrocarbon chains subsystems of lipid molecules. It was shown that collective soliton-type excitations can arise in this ternary system that lead to lateral proton transport accompanied by the movement of solitons, representing localized regions of compression in the subsystem of lipid polar groups and structural defects in the subsystem of hydrocarbon chains of lipid molecules. The results of modelling revealed that lateral proton transport in this coupled system is independent of the electric field along the membranes and can be determined by membrane curvature and elastic stress generated by proteins and ion channels embedded in biomembranes.