title: Molecular organization of cholesterol in polyunsaturated phospholipid membranes: a solid state 2H NMR investigation.
abstract: We compared the molecular organization of equimolar [3alpha-2H1]cholesterol in 18:0-18:1PC (1-stearoyl-2-oleoylphosphatidylcholine), 18:0-22:6PC (1-stearoyl-2-docosahexaenoylphosphatidylcholine), 18:0-20:4PC (1-stearoyl-2-arachidonylphosphatidylcholine) and 20:4-20:4PC (1,2-diarachidonylphosphatidylcholine) bilayers by solid state 2H NMR. Essentially identical quadrupolar splittings (delta v(r) = 45 +/- 1 kHz) corresponding to the same molecular orientation characterized by tilt angle alpha0 = 16 +/- 1 degrees were measured in 18:0-18:1PC, 18:0-22:6PC and 18:0-20:4PC. A profound difference in molecular interaction with dipolyunsaturated 20:4-20:4PC, in contrast, is indicated for the sterol. Specifically, the tilt angle alpha0 = 22 +/- 1 degrees (derived from delta v(r) = 37 +/- 1 kHz) is greater and its membrane intercalation is only 15 mol%.
authors.affiliation: Department of Physics, Indiana University-Purdue University Indianapolis, 46202, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Brzustowicz
authors.forename: W
authors.initials: W
authors.lastname: Stillwell
authors.forename: S R
authors.initials: SR
authors.lastname: Wassall
mesh_terms: D002151:Calorimetry; D002784:Cholesterol / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids / Q000737:chemistry*; D008956:Models, Chemical; D017433:Protein Structure, Secondary
chemical_list: D008563:Membrane Lipids; D002784:Cholesterol