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Full-Text Articles in Physical Sciences and Mathematics
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 …
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, …
Structure Of Fully Hydrated Fluid Phase Lipid Bilayers With Monounsaturated Chains., Norbert Kucerka, Stephanie Tristram-Nagle, John Nagle
Structure Of Fully Hydrated Fluid Phase Lipid Bilayers With Monounsaturated Chains., Norbert Kucerka, Stephanie Tristram-Nagle, John Nagle
Prof. Stephanie Tristram-Nagle Ph.D.
Quantitative structures are obtained at 30 degrees C for the fully hydrated fluid phases of palmitoyloleoylphosphatidylcholine (POPC), with a double bond on the sn-2 hydrocarbon chain, and for dierucoylphosphatidylcholine (di22:1PC), with a double bond on each hydrocarbon chain. The form factors F(qz) for both lipids are obtained using a combination of three methods. (1) Volumetric measurements provide F(0). (2) X-ray scattering from extruded unilamellar vesicles provides /F(qz)/ for low q(z). (3) Diffuse X-ray scattering from oriented stacks of bilayers provides /F(qz)/ for high q(z). Also, data using method (2) are added to our recent data for dioleoylphosphatidylcholine (DOPC) using methods …
Polyunsaturated Docosahexaenoic Vs Docosapentaenoic Acid-Differences In Lipid Matrix Properties From The Loss Of One Double Bond., Nadukkudy Eldho, Scott Feller, Stephanie Tristram-Nagle, Ivan Polozov, Klaus Gawrisch
Polyunsaturated Docosahexaenoic Vs Docosapentaenoic Acid-Differences In Lipid Matrix Properties From The Loss Of One Double Bond., Nadukkudy Eldho, Scott Feller, Stephanie Tristram-Nagle, Ivan Polozov, Klaus Gawrisch
Prof. Stephanie Tristram-Nagle Ph.D.
Insufficient supply to the developing brain of docosahexaenoic acid (22:6n3, DHA), or its omega-3 fatty acid precursors, results in replacement of DHA with docosapentaenoic acid (22:5n6, DPA), an omega-6 fatty acid that is lacking a double bond near the chain's methyl end. We investigated membranes of 1-stearoyl(d(35))-2-docosahexaenoyl-sn-glycero-3-phosphocholine and 1-stearoyl(d(35))-2-docosapentaenoyl-sn-glycero-3-phosphocholine by solid-state NMR, X-ray diffraction, and molecular dynamics simulations to determine if the loss of this double bond alters membrane physical properties. The low order parameters of polyunsaturated chains and the NMR relaxation data indicate that both DHA and DPA undergo rapid conformational transitions with correlation times of the order of …