Chiral Molecular Self-Assembly of Phospholipid Tubules: A Circular Dichroism Study

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 93; no. 23; pp. 12943 - 12946
• Main Authors: Spector, Mark S., Kalpathy R. K. Easwaran, Jyothi, Ghanta, Selinger, Jonathan V., Singh, Alok, Schnur, Joel M.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 12.11.1996; National Acad Sciences; National Academy of Sciences; The National Academy of Sciences of the USA
• Subjects: Absorption spectra; Alcohols; Biological Sciences; Chirality; Circular Dichroism; Dichroism; Dimyristoylphosphatidylcholine - chemistry; Diynes; Lipids; Liposomes; Microscopy, Electron; Models, Biological; Molecular Conformation; Molecular structure; Molecules; Phosphatidylcholines - chemistry; Phospholipids; Phospholipids - chemistry; Solvents; Structure-Activity Relationship; Water
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.93.23.12943

We report on spectroscopic studies of the chiral structure in phospholipid tubules formed in mixtures of alcohol and water. Synthetic phospholipids containing diacetylenic moieties in the acyl chains self-assemble into hollow, cylindrical tubules in appropriate conditions. Circular dichroism provides a direct measure of chirality of the molecular structure. We find that the CD spectra of tubules formed in mixtures of alcohol and water depends strongly on the alcohol used and the lipid concentration. The relative spectral intensity of different circular dichroism bands correlates with the number of bilayers observed using microscopy. The results provide experimental evidence that tubule formation is based on chiral packing of the lipid molecules and that interbilayer interactions are important to the tubule structure.