Inositolphosphoglycan mediators structurally related to glycosyl phosphatidylinositol anchors: Synthesis, structure and biological activity

The preparation of the pseudopentasaccharide 1a, an inositolphosphoglycan ( IPG) that contains the conserved linear structure of glycosyl phosphatidyli nositol anchors (GPI anchors), was carried out by using a highly convergent 2+3-block synthesis approach which involves imidate and sulfoxide glycosyl ation reactions. The preferred solution conformation of this structure was determined by using NMR spectroscopy and molecular dynamics simulations pri or to carrying out quantitative structure-activity relationship studies in connection with the insulin signalling process. The ability of 1a to stimul ate lipogenesis in rat adipocites as well as to inhibit cAMP dependent prot ein kinase and to activate pyruvate dehydrogenase phosphatase was investiga ted. Compound 1a did not show any significant activity, which may be taken as a strong indication that the GPI anchors are not the precursors of the I PG mediators.