Interaction of L-alpha-didecanoyl phosphatidylcholine with the AI polypeptide of high density lipoprotein.

Abstract
Cooperative interaction of L-.alpha.-didecanoyl phosphatidylcholine with the AI polypeptide from human serum high density lipoprotein results in a complex particle containing 2 molecules of AI and 190 molecules of the lipid. Binding occurs 2 orders of magnitude above the critical micelle concentration of the lipid and requires the simultaneous presence of low levels of single-chain amphiphiles. The present investigation and previous studies from this laboratory suggest that AI contains pockets capable of interacting with a fixed hydrophobic volume and that amphiphilic head groups do not affect the binding capacity.