John M. Seddon

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The phase behavior of 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE) in excess water has been studied by differential scanning calorimetry and x-ray diffraction. In addition to the usual gel phase L beta of lamellar periodicity 5.07 nm and the fluid bilayer phase L alpha of periodicity 4.5 nm, two distinct crystalline forms may also be spontaneously(More)
The phase behaviour and structural parameters of a homologous series of saturated diacyl phosphatidylcholine/fatty acid 1:2 (mol/mol) mixtures having chain lengths from C12 to C20 were studied by X-ray diffraction and calorimetry, as a function of water content. The chain-melting transition temperatures of the 1:2 PC/FA mixtures are found to be largely(More)
The structure and polymorphism of a homologous series of diacyl- and of dialkylphosphatidylethanolamines have been investigated by X-ray diffraction, calorimetry, and density measurement. The compositional dependence of the repeat spacings of the gel (L beta or L beta'), fluid bilayer (L alpha), and inverted hexagonal (HII) phases has been determined both(More)
Intra- and interobserver (n = 3) variability of sizing and counting microbubbles using optical microscopy (OM) was assessed. The system was calibrated using standardised mono-disperse and poly-disperse microspheres. Results of the calibration show intraobserver variations of number count (C) = 13.0% and arithmetic mean size (MS) = 0.2%, and interobserver(More)
The structure and biological function of the DNA double helix are based on interactions recognizing sequence complementarity between two single strands of DNA. A single DNA strand can also recognize the double helix sequence by binding in its groove and forming a triplex. We now find that sequence recognition occurs between intact DNA duplexes without any(More)
The phase behaviour of distearoyl- and dihexadecylphosphatidylethanolamine at high salt concentration and of dipalmitoylphosphatidylcholine + 66 mol% palmitic acid at pH 4.0 have been studied by high-field 31P-NMR spectroscopy and X-ray diffraction. In saturated NaCl, dihexadecylphosphatidylethanolamine undergoes a reversible transition at 74 degrees C(More)
To investigate the properties of a pure liquid ordered (Lo) phase in a model membrane system, a series of saturated phosphatidylcholines combined with cholesterol were examined by variable temperature multinuclear (1H, 2H, 13C, 31P) solid-state NMR spectroscopy and x-ray scattering. Compositions with cholesterol concentrations>or=40 mol %, well within the(More)