Elastic properties of polyunsaturated phosphatidylethanolamines influence rhodopsin function

• DOI: 10.1039/c2fd20095c
• Publication Date: 2012-06-29T13:02:35Z
• Authors: Walter E. Teague; Olivier Soubias; Horia Petrache; Nola Fuller; Kirk G. Hines; R. Peter Rand; Klaus Gawrisch
• Keywords: 0301 basic medicine; Rhodopsin; 03 medical and health sciences; Magnetic Resonance Spectroscopy; Light; X-Ray Diffraction; Phosphatidylethanolamines; Cell Membrane; Lipid Bilayers; Phosphatidylcholines; Animals; Cattle

Membranes with a high content of polyunsaturated phosphatidylethanolamines (PE) facilitate formation of metarhodopsin-II (M(II)), the photointermediate of bovine rhodopsin that activates the G protein transducin. We determined whether M(II)-formation is quantitatively linked to the elastic properties of PEs. Curvature elasticity of monolayers of the polyunsaturated lipids 18 : 0-22 : 6(n - 3)PE, 18 : 0-22 : 5(n)- 6PE and the model lipid 18 : 1(n - 9)-18 : 1,(n- 9)PE were investigated in the inverse hexagonal phase. All three lipids form lipid monolayers with rather low spontaneous radii of curvature of 26-28 angstroms. In membranes, all three PEs generate high negative curvature elastic stress that shifts the equilibrium of MI(I)/M(II) photointermediates of rhodopsin towards M(II) formation.