Electron diffraction and imaging of epitaxially grown crystals of monogalactosyldiacylglycerol

Abstract

The molecular structure of 1,2-3-distearyl-monogalactosyldiacylglycerol (MGDG) was studied by electron microscopy and electron diffraction. MGDG was extracted from spinach leaves, purified and hydrogenated to a distearate compound. Crystals of MGDG were obtained in two orientations. Thin crystals grown from solutions by evaporation of non-polar solvent on the carbon coated grid showed the long axis of the molecules nearly perpendicular to the carbon film substrate. The acyl chains were packed in a hexagonal lattice commonly found in phospholipid crystals. In order to study the structure along the long axis of the molecule, an epitaxial method of crystal growth was used to obtain crystals with the long axis of the molecule parallel to the carbon substrate. Epitaxial crystals was grown from solutions in naphthalene or benzoic acid on 400 mesh, carbon coated grids.