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Full-Text Articles in Physics
Structure And Elasticity Of Lipid Membranes With Genistein And Daidzein Bioflavinoids Using X-Ray Scattering And Md Simulations., Mohit Raghunathan, Yuriy Zubovski, Richard Venable, Richard Pastor, John Nagle, Stephanie Tristram-Nagle
Structure And Elasticity Of Lipid Membranes With Genistein And Daidzein Bioflavinoids Using X-Ray Scattering And Md Simulations., Mohit Raghunathan, Yuriy Zubovski, Richard Venable, Richard Pastor, John Nagle, Stephanie Tristram-Nagle
Prof. Stephanie Tristram-Nagle Ph.D.
This work reports the effects of the bioflavinoids genistein and daidzein on lipid bilayers as determined by volume measurements, X-ray scattering, and molecular dynamics simulations. The experimental and simulated total molecular volumes were found to be in outstanding agreement with each other before the addition of genistein and daidzein and also after their addition. Both bioflavinoids inserted into the hydrocarbon region of both DOPC and diphytanoylPC near the carbonyls of the lipids and both decreased the bilayer thicknesses. The long axes of both bioflavinoids were oriented nearly parallel to the plane of the bilayer with their carbonyl groups preferentially pointed …
Molecular Structures Of Fluid Phase Phosphatidylglycerol Bilayers As Determined By Small Angle Neutron And X-Ray Scattering., Jianjun Pan, Frederick Heberle, Stephanie Tristram-Nagle, Michelle Szymanski, Mary Koepfinger, John Katsaras, Norbert Kucerka
Molecular Structures Of Fluid Phase Phosphatidylglycerol Bilayers As Determined By Small Angle Neutron And X-Ray Scattering., Jianjun Pan, Frederick Heberle, Stephanie Tristram-Nagle, Michelle Szymanski, Mary Koepfinger, John Katsaras, Norbert Kucerka
Prof. Stephanie Tristram-Nagle Ph.D.
We have determined the molecular structures of commonly used phosphatidylglycerols (PGs) in the commonly accepted biologically relevant fluid phase. This was done by simultaneously analyzing small angle neutron and X-ray scattering data, with the constraint of measured lipid volumes. We report the temperature dependence of bilayer parameters obtained using the one-dimensional scattering density profile model - which was derived from molecular dynamics simulations - including the area per lipid, the overall bilayer thickness, as well as other intrabilayer parameters (e.g., hydrocarbon thickness). Lipid areas are found to be larger than their phosphatidylcholine (PC) counterparts, a result likely due to repulsive …
Alamethicin Aggregation In Lipid Membranes., Jianjun Pan, Stephanie Tristram-Nagle, John Nagle
Alamethicin Aggregation In Lipid Membranes., Jianjun Pan, Stephanie Tristram-Nagle, John Nagle
Prof. Stephanie Tristram-Nagle Ph.D.
X-ray scattering features induced by aggregates of alamethicin (Alm) were obtained in oriented stacks of model membranes of DOPC(diC18:1PC) and diC22:1PC. The first feature obtained near full hydration was Bragg rod in-plane scattering near 0.11 A(-1) in DOPC and near 0.08 A(-1) in diC22:1PC at a 1:10 Alm:lipid ratio. This feature is interpreted as bundles consisting of n Alm monomers in a barrel-stave configuration surrounding a water pore. Fitting the scattering data to previously published molecular dynamics simulations indicates that the number of peptides per bundle is n = 6 in DOPC and n >or= 9 in diC22:1PC. The larger …
Lipid Bilayers: Thermodynamics, Structure, Fluctuations, And Interactions., Stephanie Tristram-Nagle, John Nagle
Lipid Bilayers: Thermodynamics, Structure, Fluctuations, And Interactions., Stephanie Tristram-Nagle, John Nagle
Prof. Stephanie Tristram-Nagle Ph.D.
This article, adapted from our acceptance speech of the Avanti Award in Lipids at the 47th Biophysical Society meeting in San Antonio, 2003, summarizes over 30 years of research in the area of lipid bilayers. Beginning with a theoretical model of the phase transition (J.F.N.), we have proceeded experimentally using dilatometry and density centrifugation to study volume, differential scanning calorimetry to study heat capacity, and X-ray scattering techniques to study structure of lipid bilayers as a function of temperature. Electron density profiles of the gel and ripple phases have been obtained as well as profiles from several fluid phase lipids, …