Horia I. Petrache

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Bilayer form factors obtained from x-ray scattering data taken with high instrumental resolution are reported for multilamellar vesicles of L alpha phase lipid bilayers of dipalmitoylphosphatidylcholine at 50 degrees C under varying osmotic pressure. Artifacts in the magnitudes of the form factors due to liquid crystalline fluctuations have been eliminated(More)
X-ray diffraction data taken at high instrumental resolution were obtained for EPC and DMPC under various osmotic pressures, primarily at T = 30 degrees C. The headgroup thickness DHH was obtained from relative electron density profiles. By using volumetric results and by comparing to gel phase DPPC we obtain areas AEPCF = 69.4 +/- 1.1 A2 and ADMPCF = 59.7(More)
Deuterium (H) NMR spectroscopy provides detailed information regarding the structural fluctuations of lipid bilayers, including both the equilibrium properties and dynamics. Experimental H NMR measurements for the homologous series of 1,2-diacyl-sn-glycero-3-phosphocholines with perdeuterated saturated chains (from C12:0 to C18:0) have been performed on(More)
The fundamental issue of interactions between lipid bilayers is addressed experimentally and theoretically. We report high-resolution x-ray scattering data for bilayers composed of three different kinds of phosphatidylcholine lipids. These data yield the interbilayer water spacing fluctuation s , as well as the traditional osmotic pressure P , both as(More)
Quantitative structures of the fully hydrated fluid phases of dimyristoylphosphatidylcholine (DMPC) and dilauroylphosphatidylcholine (DLPC) were obtained at 30 degrees C. Data for the relative form factors F(q(z)) for DMPC were obtained using a combination of four methods. 1), Volumetric data provided F(0). 2), Diffuse x-ray scattering from oriented stacks(More)
This study focuses on dioleoylphosphatidylcholine (DOPC) bilayers near full hydration. Volumetric data and high-resolution synchrotron x-ray data are used in a method that compares DOPC with well determined gel phase dipalmitoylphosphatidylcholine (DPPC). The key structural quantity obtained is fully hydrated area/lipid A0 = 72.2 +/- 1.1 A2 at 30 degrees C,(More)
An efficient method for extracting volumetric data from simulations is developed. The method is illustrated using a recent atomic-level molecular dynamics simulation of L alpha phase 1,2-dipalmitoyl-sn-glycero-3-phosphocholine bilayer. Results from this simulation are obtained for the volumes of water (VW), lipid (V1), chain methylenes (V2), chain terminal(More)
alpha-1 Antitrypsin (A1AT) is an abundant circulating serpin with a postulated function in the lung of potently inhibiting neutrophil-derived proteases. Emphysema attributable to A1AT deficiency led to the concept that a protease/anti-protease imbalance mediates cigarette smoke-induced emphysema. We hypothesized that A1AT has other pathobiological relevant(More)
Using x-ray diffraction and NMR spectroscopy, we present structural and material properties of phosphatidylserine (PS) bilayers that may account for the well documented implications of PS headgroups in cell activity. At 30 degrees C, the 18-carbon monounsaturated DOPS in the fluid state has a cross-sectional area of 65.3 A(2) which is remarkably smaller(More)
Starting from the glycophorin A dimer structure determined by NMR, we performed simulations of both dimer and monomer forms in explicit lipid bilayers with constant normal pressure, lateral area, and temperature using the CHARMM potential. Analysis of the trajectories in four different lipids reveals how lipid chain length and saturation modulate the(More)