title: The membrane potential has no detectable effect on the phosphocholine headgroup conformation in large unilamellar phosphatidylcholine vesicles as determined by 2H-NMR.
abstract: In this study the effect of a transmembrane electrical potential on the phospholipid headgroup conformation was investigated using the 2H-NMR technique. Large unilamellar vesicles were prepared of dioleoylphosphatidylcholine, specifically 2H-labeled at the alpha- or beta-position of the choline group. No conformational change of the phosphocholine headgroup could be detected after induction of a valinomycin-induced K(+)-diffusion potential across the bilayer. However, this method could be used to measure the redistribution of tetraphenylphosphonium across the bilayer in response to delta psi, which reorients the phosphocholine headgroups in the opposite bilayer-water interfaces.
authors.affiliation: Department of Biochemistry of Membranes, Utrecht University, The Netherlands.
authors.forename: J M
authors.initials: JM
authors.lastname: Leenhouts
authors.forename: V
authors.initials: V
authors.lastname: Chupin
authors.forename: J
authors.initials: J
authors.lastname: de Gier
authors.forename: B
authors.initials: B
authors.lastname: de Kruijff
mesh_terms: D052160:Benzothiazoles; D002232:Carbocyanines; D004396:Coloring Agents; D003903:Deuterium; D008051:Lipid Bilayers; D008081:Liposomes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008564:Membrane Potentials; D008968:Molecular Conformation; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D010713:Phosphatidylcholines / Q000737:chemistry*; D010715:Phosphatidylglycerols; D010767:Phosphorylcholine / Q000737:chemistry*; D013775:Tetraphenylborate
chemical_list: D052160:Benzothiazoles; D002232:Carbocyanines; D004396:Coloring Agents; D008051:Lipid Bilayers; D008081:Liposomes; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D010767:Phosphorylcholine; D013775:Tetraphenylborate; C051388:1,2-dioleoyl-sn-glycero-3-phosphoglycerol; C072030:3,3'-diethylthiacarbocyanine iodide; D003903:Deuterium; C017251:1,2-oleoylphosphatidylcholine; C013289:tetraphenylphosphonium