title: Proton Gradients as a Key Physical Factor in the Evolution of the Forced Transport Mechanism Across the Lipid Membrane.
abstract: A critical phase in the transition from prebiotic chemistry to biological evolution was apparently an asymmetric ion flow across the lipid membrane. Due to imbalance in the ion flow, the early lipid vesicles could selectively take the necessary molecules from the environment, and release the side-products from the vesicle. Natural proton gradients played a definitively crucial role in this process, since they remain the basis of energy transfer in the present-day cells. On the basis of this supposition, and the premise of the early vesicle membrane's impermeability to protons, we have shown that the emergence of the proton gradient in the lipid vesicle could be a key physical factor in the evolution of the forced transport mechanism (pore formation and active transport) across the lipid bilayer. This driven flow of protons across the membrane is the result of the electrochemical proton gradient and osmotic pressures on the integrity of the lipid vesicle. At a critical number of new lipid molecules incorporated into the vesicle, the energies associated with the creation of the proton gradient exceed the bending stiffness of the lipid membrane, and overlap the free energy of the lipid bilayer pore formation.
authors.affiliation: Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Dubravska cesta 9, 841 04, Bratislava, Slovakia. oliver.strbak@savba.sk.
authors.forename: Oliver
authors.initials: O
authors.lastname: Strbak
authors.affiliation: Astronomical Institute, Slovak Academy of Sciences, 059 60, Tatranska Lomnica, Slovakia.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Kanuchova
authors.affiliation: Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Dubravska cesta 9, 841 04, Bratislava, Slovakia.
authors.forename: Andrej
authors.initials: A
authors.lastname: Krafcik
mesh_terms: D005075:Biological Evolution; D001692:Biological Transport; D019418:Evolution, Chemical; D006863:Hydrogen-Ion Concentration; D008051:Lipid Bilayers / Q000737:chemistry*; D000069497:Origin of Life; D011522:Protons
chemical_list: D008051:Lipid Bilayers; D011522:Protons
keywords: Active transport evolution; Asymmetric ion flow; Early lipid vesicles; Pore formation; Proton gradients