Effect of membrane tension on the electric field and dipole potential of lipid bilayer membrane

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• 作者：Dora Toledo Warshaviak^a ; Michael J. Muellner^a ; Mirianas Chachisvilis ; ^a ; ^{mirianas@ljbi.org"" rel=""nofollow}
• 关键词：Dipole potential ; Lipid bilayer ; Mechanosensing ; Fluid shear stress ; GPCR ; Membrane tension
• 刊名：Biochimica et Biophysica Acta (BBA)/Biomembranes
• 出版年：2011
• 出版时间：October 2011
• 年：2011
• 卷：1808
• 期：10
• 页码：2608-2617
• 全文大小：1555 K

文摘

The dipole potential of lipid bilayer membrane controls the difference in permeability of the membrane to oppositely charged ions. We have combined molecular dynamics (MD) simulations and experimental studies to determine changes in electric field and electrostatic potential of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid bilayer in response to applied membrane tension. MD simulations based on CHARMM36 force field showed that electrostatic potential of DOPC bilayer decreases by ~ 45 mV in the physiologically relevant range of membrane tension values (0 to 15 dyn/cm). The electrostatic field exhibits a peak (~ 0.8 × 10⁹ V/m) near the water/lipid interface which shifts by 0.9 Å towards the bilayer center at 15 dyn/cm. Maximum membrane tension of 15 dyn/cm caused 6.4 % increase in area per lipid, 4.7 % decrease in bilayer thickness and 1.4 % increase in the volume of the bilayer. Dipole-potential sensitive fluorescent probes were used to detect membrane tension induced changes in DOPC vesicles exposed to osmotic stress. Experiments confirmed that dipole potential of DOPC bilayer decreases at higher membrane tensions. These results are suggestive of a potentially new mechanosensing mechanism by which mechanically induced structural changes in the lipid bilayer membrane could modulate the function of membrane proteins by altering electrostatic interactions and energetics of protein conformational states.