title: Genetic encoding of a bicyclo[6.1.0]nonyne-charged amino acid enables fast cellular protein imaging by metal-free ligation.
abstract: Visualizing biomolecules by fluorescent tagging is a powerful method for studying their behaviour and function inside cells. We prepared and genetically encoded an unnatural amino acid (UAA) that features a bicyclononyne moiety. This UAA offered exceptional reactivity in strain-promoted azide-alkyne cycloadditions. Kinetic measurements revealed that the UAA reacted also remarkably fast in the inverse-electron-demand Diels-Alder cycloaddition with tetrazine-conjugated dyes. Genetic encoding of the new UAA inside mammalian cells and its subsequent selective labeling at low dye concentrations demonstrate the usefulness of the new amino acid for future imaging studies.
authors.affiliation: Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
authors.forename: Annika
authors.initials: A
authors.lastname: Borrmann
authors.forename: Sigrid
authors.initials: S
authors.lastname: Milles
authors.forename: Tilman
authors.initials: T
authors.lastname: Plass
authors.forename: Jan
authors.initials: J
authors.lastname: Dommerholt
authors.forename: Jorge M M
authors.initials: JM
authors.lastname: Verkade
authors.forename: Manfred
authors.initials: M
authors.lastname: Wiessler
authors.forename: Carsten
authors.initials: C
authors.lastname: Schultz
authors.forename: Jan C M
authors.initials: JC
authors.lastname: van Hest
authors.forename: Floris L
authors.initials: FL
authors.lastname: van Delft
authors.forename: Edward A
authors.initials: EA
authors.lastname: Lemke
mesh_terms: D000480:Alkynes / Q000737:chemistry; D001386:Azides / Q000737:chemistry; D001643:Bridged Bicyclo Compounds / Q000737:chemistry*; D002232:Carbocyanines / Q000737:chemistry; D057930:Click Chemistry; D003374:Coumarins / Q000737:chemistry; D061565:Cycloaddition Reaction; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D008239:Lysine / Q000138:chemical synthesis / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D015202:Protein Engineering; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism
chemical_list: D000480:Alkynes; D001386:Azides; D001643:Bridged Bicyclo Compounds; D002232:Carbocyanines; D003374:Coumarins; D005456:Fluorescent Dyes; D011506:Proteins; C556617:bicyclo(6.1.0)nonyne; C085321:cyanine dye 5; D012343:RNA, Transfer; C030123:coumarin; D008239:Lysine