ABSTRACT
This chapter discusses the work on the effects of an asymmetry in the length of the two constituent hydrocarbon chains on the bilayer properties of mixed-chain-length phospholipids. The magnitude of the chain-length asymmetry will also be shown to determine the morphology of the phospholipid assemblies at temperatures above the chain-melting phase-transition temperature of the phospholipids. The interpretation of the results of our studies with mixed-chain-length phospholipids has relied heavily on a detailed knowledge of the preferred molecular conformation of phospholipids. The phospholipids in Region I are organized into lamellar structures at all temperatures and adopt either a noninterdigitated or a partially interdigitated acyl chain packing conformation in the bilayer gel phase. The phospholipids in Region II are organized into lamellar structures at all temperatures and adopt a mixed-interdigitated acyl chain packing conformation in the bilayer gel phase. Raman spectroscopic measurements were carried out on the mixed-chain-length PCs to determine the validity of this interpretation.
