Dynamic structure and phase behavior of dimyristoylphosphatidylethanolamine bilayers studied by deuterium nuclear magnetic resonance

Abstract

The dynamic structure of dimyristoylphosphatidylethanolamine [DMPE] bilayers was studied by 2H NMR spectroscopy of the perdeuterated sn-2 chain. The order parameter profile of the lipid chains in the fluid phase is qualitatively similar to that found for other phospholipids, but the order parameter plateau is .apprx. 15% higher than found for dimyristoylphosphatidylcholine at a comparable reduced temperature. The chains of DMPE undergo a segmental motion in the gel phase, which for segments close to the end of the chain approximates continuous axial diffusion. In the phase-transition region, spectra are observed that can be best described in terms of the interconversion of coexisting lipid phases through the transition.