Structure of the L_c' phase in a hydrated lipid multilamellar system

Abstract

In this Letter we establish the structure of the L_c' phase exhibited by the lipid dipalmitoylphosphatidylcholine (DPPC) under hydration. On the basis of X-ray diffraction data on oriented multibilayers, we show that the structure of this phase is characterized by two lattices: a molecular superlattice and a hydrocarbon chain sublattice. Diffraction data available in the literature suggest the presence of similar molecular superlattices in the L_c' phase of various other lipid-water systems.