Cholesterol effects on ripple structure studied by small-angle neutron and X-ray diffraction

Abstract

Neutron diffraction was used to examine the cholesterol distribution in the ripple phase of dipalmitoylphosphatidylcholine (DPPC) mixed with cholesterol. The neutron-diffraction intensity profiles were analyzed to reconstruct diffraction profiles on the basis of models. We examined three models with different cholesterol distributions. The diffraction profile reconstructed from a model in which two microdomains are formed agrees best with the observed profile. The result indicates the existence of microdomains in the DPPC-cholesterol mixture ripple phase.