Arrangement of lipid and protein in human serum high density lipoproteins: a proposed model.

Based on size and compositional data, models for the two major density subclasses of human serum high density lipoproteins have been developed. Descriptions of both the surface structure of the high density lipoproteins and the structure of their apolar core regions are integral parts of these models. The surface is described as a mosaic of amphiphilic lipid and helical protein regions. The conformation and orientation of the various apolar lipid components as restricted by the surface organization is discussed.