Internalization of a peptide into multilamellar vesicles assisted by the formation of an alpha-oxo oxime bond

As part of a drug-delivery project, we designed and synthesised a novel hydroxylamine cholesterol-based anchor to ensure the chemoselective ligation of recognition patterns onto multilamellar vesicles by oxime ligation. The entry of a glyoxylyl peptide into the vesicles was unexpectedly assisted by the formation of the alpha-oxo oxime bond. We studied extensively the kinetic and thermodynamic aspects of this phenomenon. Briefly, for a glyoxylyl peptide, the speed and ability to enter the vesicle were dependent upon 1) the presence of a hydroxylamine anchor of the type CholE3ONH2, 2) the amount of peptide engaged in the ligation and 3) the flip-flop motion permitted by the different formulations, in which the presence of cholesterol seems to play an important role.