Functional differentiation of amphiphilic helices of the apolipoproteins by hydrophobic moment analysis.

The amphiphilic character of different plasma apolipoproteins was investigated by a combination of established hydrophobicity analysis methods. These methods proved to be powerful in the detection of amphiphilic phospholipid-binding domains. Within this class of lipid-binding domains, lecithin-cholesterol acyltransferase activating and non-activating helices could be differentiated by calculating hydrophobic moments at different angles. We conclude that the hydrophobic characteristics of the different helices determined the mode of lipid binding and the substrate properties of these phospholipid-protein complexes for the lecithin-cholesterol acyltransferase reaction.