Water-soluble, substrate for sortase mediated labeling of proteins. Sortase catalyzes a transpeptidase reaction between a specific internal sequence of a protein and an amine group present on the N-terminus of triglycine recently has become an area of great interest. This method of labeling proteins has been denoted as “Sortagging”. Proteins conjugated to DBCO-Gly-Gly-Gly can be further modified with azide-containing molecules creating site-specific protein conjugates. Examples of creating protein conjugates using sortagging include site-specifically PEGylating proteins,1 site-specific protein-lipid conjugates,2 and constructing peptides and glycosylphosphatidylinositol chimeras.3 Sortase has also been used in peptide synthesis to cyclize peptides to create macrocyclic peptides, glycopeptides4 and protein−protein conjugates.
