Total synthesis of a glycosylphosphatidylinositol anchor of the human lymphocyte CD52 antigen

The first total synthesis of a glycosylphosphatidylinositol (GPI) anchor bearing a polyunsaturated arachidonoyl fatty acid is reported. This lipid is found in mammalian GPIs that do not undergo lipid remodeling, a process that has important implications in the localization and function of GPI-anchored proteins. Incorporation of the oxidation- and reduction-sensitive arachidonoyl lipid in the target GPI was accomplished by using the para-methoxybenzyl (PMB) group for permanent hydroxyl group protection, which featured a selective, rapid, and efficient global deprotection protocol. The flexibility of this synthetic strategy was further highlighted by the inclusion of two additional GPI core structural modifications present in the GPI anchor of the human lymphocyte CD52 antigen. Lipid diversity in GPI synthesis: The convergent synthesis of an arachidonoyl-containing glycosylphosphatidylinositol (GPI) anchor of the human lymphocyte CD52 antigen is reported. Incorporation of the oxidation- and reduction-sensitive polyunsaturated arachidonoyl lipid, as well as two additional GPI core modifications (see structure), was enabled by using a para-methoxybenzyl (PMB)-based global protection strategy.