title: Copper-free click reactions with polar bicyclononyne derivatives for modulation of cellular imaging.
abstract: The ability of cells to incorporate azidosugars metabolically is a useful tool for extracellular glycan labelling. The exposed azide moiety can covalently react with alkynes, such as bicyclo[6.1.0]nonyne (BCN), by strain-promoted alkyne-azide cycloaddition (SPAAC). However, the use of SPAAC can be hampered by low specificity of the cycloalkyne. In this article we describe the synthesis of more polar BCN derivatives and their properties for selective cellular glycan labelling. The new polar derivatives [amino-BCN, glutarylamino-BCN and bis(hydroxymethyl)-BCN] display reaction rates similar to those of BCN and are less cell-permeable. The labelling specificity in HEK293 cells is greater than that of BCN, as determined by confocal microscopy and flow cytometry. Interestingly, amino-BCN appears to be highly specific for the Golgi apparatus. In addition, the polar BCN derivatives label the N-glycan of the membrane calcium channel TRPV5 in HEK293 cells with significantly enhanced signal-to-noise ratios.
authors.affiliation: Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen (The Netherlands); Physiology, Radboud University Medical Centre, P.O. Box 9101, 6500 HB Nijmegen (The Netherlands).
authors.forename: E H P
authors.initials: EH
authors.lastname: Leunissen
authors.forename: M H L
authors.initials: MH
authors.lastname: Meuleners
authors.forename: J M M
authors.initials: JM
authors.lastname: Verkade
authors.forename: J
authors.initials: J
authors.lastname: Dommerholt
authors.forename: J G J
authors.initials: JG
authors.lastname: Hoenderop
authors.forename: F L
authors.initials: FL
authors.lastname: van Delft
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D001386:Azides / Q000737:chemistry*; D001643:Bridged Bicyclo Compounds / Q000032:analysis / Q000138:chemical synthesis*; D057930:Click Chemistry; D061565:Cycloaddition Reaction; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000032:analysis / Q000138:chemical synthesis*; D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D018613:Microscopy, Confocal; D061848:Optical Imaging; D011134:Polysaccharides / Q000032:analysis* / Q000737:chemistry
chemical_list: D000480:Alkynes; D001386:Azides; D001643:Bridged Bicyclo Compounds; D005456:Fluorescent Dyes; D011134:Polysaccharides; C556617:bicyclo(6.1.0)nonyne
keywords: BCN; HEK293 cells; SPAAC; click chemistry; glycosylation; imaging agents