Polymorphic forms of 1,2-dipalmitoyl-sn-glycerol: a combined X-ray and electron diffraction study

Area of Science:

• Crystallography
• Materials Science
• Biochemistry

Background:

• Polymorphism in lipids affects their physical and chemical properties.
• Understanding lipid crystal structures is crucial for applications in pharmaceuticals and food science.

Purpose of the Study:

• To elucidate the crystallographic structures of two polymorphic forms of 1,2-dipalmitoyl-sn-glycerol.
• To correlate structural differences with observed stability and properties.

Main Methods:

• Single crystal X-ray diffraction for the beta'L-form.
• Lamellar electron diffraction for the alpha L-form.
• Molecular modeling and structure solution.

Main Results:

• The beta'L-form exhibits hairpin conformers with inclined acyl chain packing.
• The alpha L-form features perpendicular acyl chain packing in a hexagonal subcell.
• A distinct molecular conformation and hydroxyl oxygen positioning in the alpha L-form explain its enhanced stability.

Conclusions:

• The study provides detailed structural insights into 1,2-dipalmitoyl-sn-glycerol polymorphism.
• Structural differences directly correlate with the stability of different crystal forms.
• Findings contribute to the understanding of lipid behavior and packing.