title: Metabolic delivery of ketone groups to sialic acid residues. Application To cell surface glycoform engineering.
abstract: The development of chemical strategies for decorating cells with defined carbohydrate epitopes would greatly facilitate studies of carbohydrate-mediated cell surface interactions. This report describes a general strategy for engineering the display of chemically defined oligosaccharides on cell surfaces that combines the concepts of metabolic engineering and selective chemical reactivity. Using a recently described method (Mahal, L. K., Yarema, K. J., and Bertozzi, C. R. (1997) Science 276, 1125-1128), we delivered a uniquely reactive ketone group to endogenous cell surface sialic acid residues by treating cells with the ketone-bearing metabolic precursor N-levulinoylmannosamine (ManLev). The ketone undergoes highly selective condensation reactions with complementary nucleophiles such as aminooxy and hydrazide groups. The detailed quantitative parameters of ManLev metabolism in human and nonhuman-derived cell lines were determined to establish a foundation for the modification of cell surfaces with novel epitopes at defined cell-surface densities. Ketones within the glycoconjugates on ManLev-treated cells were then reacted with synthetic aminooxy and hydrazide-functionalized carbohydrates. The remodeled cells were endowed with novel lectin binding profiles as determined by flow cytometry analysis. The simplicity and generality of this method make it well suited for use in the study of carbohydrate-mediated cell surface interactions.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720 and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Yarema
authors.forename: L K
authors.initials: LK
authors.lastname: Mahal
authors.forename: R E
authors.initials: RE
authors.lastname: Bruehl
authors.forename: E C
authors.initials: EC
authors.lastname: Rodriguez
authors.forename: C R
authors.initials: CR
authors.lastname: Bertozzi
mesh_terms: D000818:Animals; D019556:COS Cells / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D002522:Chlorocebus aethiops; D000939:Epitopes / Q000378:metabolism*; D005434:Flow Cytometry; D006001:Glycoconjugates / Q000378:metabolism*; D006031:Glycosylation; D006367:HeLa Cells / Q000378:metabolism; D006595:Hexosamines / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells / Q000378:metabolism; D007659:Ketones / Q000378:metabolism*; D051379:Mice; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism
chemical_list: D000939:Epitopes; D006001:Glycoconjugates; D006595:Hexosamines; D007659:Ketones; C105871:N-levulinoyl mannosamine; C115916:N-levulinoylsialic acid; D009844:Oligosaccharides; D012794:Sialic Acids; D019158:N-Acetylneuraminic Acid