1 2 dimyristoyl sn glycero 3 phosphatidylglycerol

1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC) , 1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol (DMPG) and 1,2-distearoyl-sn-glycero-3-phosphatidylethanolamine-N-［methoxy (polyethylene glycol) -2000］ ( mDSPE-PEG 2000 ) were purchased from Avanti Polar Lipids and used with no purification. Phosphate buffered saline (PBS) in tablet form (pH 7.4) were purchased from Sigma-Aldrich Company Ltd. All the solvents used in the analysis were of analytical grade and were purchased from Sigma-Aldrich Company Ltd. Water used in the process of liposome preparation was of milli-Q grade with resistivity 18.2 MΩ.cm -1 .

The lipids 1,2-dihexanoyl-sn-glycero-3-phosphatidylcholine (DHPC), 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC), and 1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol (DMPG) were purchased as dry powders from Avanti Polar Lipids Inc. (Alabaster, AL, USA). Bicelle samples were prepared by suspending the appropriate amount of DMPC, DHPC and DMPG in 50 mM NaPB at pH 6.5, to achieve a [DMPC/DHPC] or [(DMPC:DMPG)/DHPC] molar ratio (q) of 0.5, and a total concentration of 250 mM of lipid mix. DHPC and DMPC were combined at 66.6:33.4 molar ratio to prepare neutral bicelles, while a combination of DHPC:DMPC:DMPG at 66.6:16.7:16.7 ratio was used to formulate negatively charged bicelles. The procedure followed a published protocol [32, (link)33] (link) and involved 10 freeze-thaw cycles alternated with vortexing, resulting in a uniform transparent non-viscous emulsion in 50 mM NaBP. For NMR analysis, 1 mM EDTA and 1 mM of TCEP were added.