Browsing by Author "Leung, A"
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- ItemSynthesis of perdeuterated 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine ([D82]POPC) for neutron studies on bilayer lipid membranes(International Conference on Neutron Scattering, 2017-07-12) Yepuri, NR; Darwish, TA; Leung, A; Krause-Heuer, AM; Wacklin, HP; Delhom, R; Holden, PJThe complexity of the chemical synthesis of completely deuterium-labelled unsaturated lipids has meant that most neutron experiments, to date, have been restricted to saturated phospholipid species, the behaviour of which under physiological conditions may not be representative of the unsaturated varieties found in biological membranes. Unsaturated lipids occur widely in nature and are crucial for the fluidity of cell membranes. Biologically relevant phospholipids such as 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) are typically asymmetric and cis-9 unsaturated in the sn-2-acyl chain, where as the sn-1 chain is often saturated. Commercially available sn-1 chain deuterated [D31]1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine([D31]POPC) does not provide enough contrast for detailed structural investigation through neutron studies, and is nearly perfectly contrast-matched to most proteins and membrane binding peptides in heavy water, which makes them neutron invisible. With this background in mind, we have developed a method for the synthesis of perdeuterated POPC and its partially labelled form. The structure of a supported bilayer membrane formed from these lipids was determined by measuring neutron reflectivity in a series of solvent contrasts, which will be discussed in this paper.
- ItemSynthesis of perdeuterated and selectively deuterated phospholipids and lipids for neutron applications(Australian Institute of Nuclear Science and Engineering, 2016-11-29) Yepuri, NR; Darwish, TA; Krause-Heuer, AM; Leung, A; Cagnes, MP; Holden, PJThe National Deuteration Facility (NDF) is focused on the provision of deuterated molecules which extends the options for contrast in neutron scattering to encompass not only solvent but molecular deuteration. Over the past few years the NDF has expanded its synthesis capability from simple deuterated fatty acids to complex deuterated molecules including lipids and phospholipids. We are now able to produce head or tail deuterated lipids including phospholipids based on oleic acid with a range of head groups (Fig. 1). These include perdeuterated 1,2-oleoyl-sn-glycero-3-phosphocholine (POPC), selectively deuterated POPC, branched chain (phytanic) phospholipids 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhyPC), and perdeuterated mono oleoyl glycerol and phytanoyl monoethanolamide. These lipids have been extensively used in constructing biologically more relevant model membranes and lipidic matrices for investigations using neutron studies. These include structural and dynamical studies of biomimetic membranes and the encapsulation of biomolecules in lipid-based bicontinuous cubic phases for drug-delivery, membrane protein crystallization, and biosensor applications. Details about design, synthesis and characterisation of these deuterated precursors and final compound will be presented.