title: Is flexoelectricity the coupling factor between chemical energy and osmotic work in the pump? A model of pump.
abstract: The following pump model is proposed. A gate is responsible for pump specificity. The actual driving force of the transport of ions against the electrochemical potential gradient is the electric field originating from an altered curvature of the phospholipid bilayer around the pump. The physical origin of this curvature-induced electric field arises from a basic liquid crystal property of lipid bilayers called flexoelectricity. Alterations occurring in phospholipid bilayer arrangement are due to changed conformation of protein; the main energy source of this change is ATP. Consequently, the energy of ATP is transformed, in our pump model, into osmotic work in following steps: ATP + protein (conformation I)----protein (conformation II)----alterations in phospholipid bilayer arrangement----electric field----active transport of ions. This model is the most simple one. In Na, K-pump there is a bidirectional ion transport. In our model of Na, K-pump three conformational states of pump proteins and two different electric fields formed sequentially in opposite directions are supposed.
mesh_terms: D001674:Bioelectric Energy Sources; D001693:Biological Transport, Active; D007473:Ion Channels; D008051:Lipid Bilayers / Q000502:physiology*; D008564:Membrane Potentials; D008954:Models, Biological; D009997:Osmotic Pressure; D011188:Potassium / Q000378:metabolism; D011487:Protein Conformation; D012964:Sodium / Q000378:metabolism
chemical_list: D007473:Ion Channels; D008051:Lipid Bilayers; D012964:Sodium; D011188:Potassium