Interaction of apolipoprotein AI from human serum high-density lipoprotein with egg yolk phosphatidylcholine.

Apolipoprotein AI from human serum high-density lipoprotein has been recombined with egg yolk lecithin from ternary complexes of detergent-lipid-protein to from homogeneous spherical particles with maximum binding of 220 mol of lipid/2 mol of AI. This complex differs from those formed when n-alkyl detergents or short chain saturated diacylphosphatidylcholines interact with AI in that the maximum hydrophobic volume accommodated by the protein is increased as the result of increased alpha-helix content. Additionally, it is shown that no interaction occurs between AI and didecanolyphosphatidylcholine or egg yolk lecithin above their thermotropic phase transitions and in the absence of single-tail amphiphiles.