Abstract: The present invention provides isolated homogeneous polyfunctionalized proteins (e.g., erythropoietin), isolated glycopeptides, and a method for preparing polyfunctionalized peptides and/or proteins via cysteine-free native chemical ligation. In certain embodiments, the invention provides an isolated homogeneous polyfunctionalized protein having the structure (I). In certain other embodiments, the invention provides an isolated glycopeptide having Formula (II). In certain other embodiments, the inventive method is a method for preparing a polyfunctionalized peptide comprising a peptidic backbone made up of four or more amino acids, wherein two or more non-adjacent amino acids are independently substituted with a moiety having the structure (III) -LH. wherein A and L1 are as defined herein.

Abstract: The present invention provides isolated homogeneous polyfunctionalized proteins (e.g., erythropoietin), isolated glycopeptides, and a method for preparing polyfunctionalized peptides and/or proteins via cysteine-free native chemical ligation. In certain embodiments, the invention provides an isolated homogeneous polyfunctionalized protein having the structure (I). In certain other embodiments, the invention provides an isolated glycopeptide having Formula (II). In certain other embodiments, the inventive method is a method for preparing a polyfunctionalized peptide comprising a peptidic backbone made up of four or more amino acids, wherein two or more non-adjacent amino acids are independently substituted with a moiety having the structure (III)-LH. wherein A and L1 are as defined herein.