title: Copper-free click chemistry for dynamic in vivo imaging.
abstract: Dynamic imaging of proteins in live cells is routinely performed by using genetically encoded reporters, an approach that cannot be extended to other classes of biomolecules such as glycans and lipids. Here, we report a Cu-free variant of click chemistry that can label these biomolecules rapidly and selectively in living systems, overcoming the intrinsic toxicity of the canonical Cu-catalyzed reaction. The critical reagent, a substituted cyclooctyne, possesses ring strain and electron-withdrawing fluorine substituents that together promote the [3 + 2] dipolar cycloaddition with azides installed metabolically into biomolecules. This Cu-free click reaction possesses comparable kinetics to the Cu-catalyzed reaction and proceeds within minutes on live cells with no apparent toxicity. With this technique, we studied the dynamics of glycan trafficking and identified a population of sialoglycoconjugates with unexpectedly rapid internalization kinetics.
authors.affiliation: Department of Chemistry, and Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA.
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Baskin
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Prescher
authors.forename: Scott T
authors.initials: ST
authors.lastname: Laughlin
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Agard
authors.forename: Pamela V
authors.initials: PV
authors.lastname: Chang
authors.forename: Isaac A
authors.initials: IA
authors.lastname: Miller
authors.forename: Anderson
authors.initials: A
authors.lastname: Lo
authors.forename: Julian A
authors.initials: JA
authors.lastname: Codelli
authors.forename: Carolyn R
authors.initials: CR
authors.lastname: Bertozzi
mesh_terms: D000818:Animals; D001692:Biological Transport; D016466:CHO Cells; D002384:Catalysis; D002470:Cell Survival; D002625:Chemistry, Organic / Q000379:methods*; D003300:Copper / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D004705:Endocytosis; D006801:Humans; D006844:Hydrocarbons, Cyclic / Q000138:chemical synthesis / Q000737:chemistry; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis / Q000737:chemistry; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019169:Jurkat Cells; D007700:Kinetics; D011134:Polysaccharides / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D013997:Time Factors
chemical_list: D006844:Hydrocarbons, Cyclic; D006845:Hydrocarbons, Fluorinated; D011134:Polysaccharides; D011506:Proteins; D003300:Copper