Lipid organization and dynamics of the monostearoylglycerol-water system. A H-2 NMR study

Deuterium labeled monostearoylglycerols with fully ([H-2(35)]-MSG) and sele ctively ([11-H-2(2)]-MSG) deuterated chains have been synthesized and used as a probe for H-2 NMR. At low temperature monoglyceride-water systems form the coagel or crystalline phase, which transforms with increasing temperat ure subsequently into the gel, liquid crystalline and cubic phase. The H-2 NMR spectra exhibit characteristic features: representative of these phases . The gel phase is metastable and gradually transforms into the coagel at t emperatures below 40 degreesC. The undercooled cubic phase transforms into the liquid crystalline phase during days. In the liquid crystalline phase. the chain order profile indicates an increase of the chain flexibility towa rds the methyl group. In the liquid crystalline phase, bilayers spontaneous ly align in a magnetic field with their normal perpendicular to the held. T he results demonstrate that H-2 NMR can serve as a convenient tool to study both structure and dynamics of different monoglyceride water phases. (C) 2 001 Elsevier Science Ireland Ltd. All rights reserved.