Solid-phase glycopeptide synthesis of tyrosine-glycosylated glycogenin fragments as substrates for glucosylation by glycogenin

Abstract

The four building blocks N^α-Fmoc-Tyr(Bz₄-α-D-Glc)-OPfp 1, N^α-Fmoc-Tyr(Bz₄-β-D-Glc)-OPfp 2, N^α-Fmoc-Tyr[Bz₄-α-D-Glc(1→4)-Bz₃-α-D-Glc]-OPfp 3 and N^α-Fmoc-Tyr[Ac₄-α-D-Glc(1→4)-Ac₃-β-D-Glc]-OPfp 4 were used in continuous-flow solid-phase synthesis of four 25-amino-acid-long glycopeptides 5–8 related to glycogenin. The unglycosylated peptide 9 was synthesized as well, and the five glycogenin fragments were tested as acceptors for glucosyl transfer by recombinant glycogenin.