Glycoprotein Labeling with Click Chemistry (GLCC)

Protein labeling is an essential technique to research in life science. Here, a method for glycoprotein labeling through glycan replacement, termed as glycoprotein labeling with click chemistry (GLCC), is described. In this method, a glycoprotein is first treated with specific glycosidases or chemicals to remove certain sugar residues, which creates acceptor sites for a specific glycosyltransferase. A clickable monosaccharide is then installed to these sites by the glycosyltransferase. The modified glycoprotein is then conjugated to a reporter molecule using a click chemistry reaction. For labeling proteins or glycoproteins that already contain vacant glycosylation sites, such as proteins purified from E.coli, deglycosylation is not needed before the labeling step. As demonstrations, labeling on bovine fetuin, mouse immunoglobulin IgG and bacterial expressed human TNFα and TNFβ are shown. Compared to traditional way of protein labeling, labeling with GLCC is through glycosylation sites, therefore is more ...