title: Single-step azide introduction in proteins via an aqueous diazo transfer.
abstract: The controlled introduction of azides in proteins provides targetable handles for selective protein manipulation. We present here an efficient diazo transfer protocol that can be applied in an aqueous solution, leading to the facile introduction of azides in the side chains of lysine residues and at the N-terminus of enzymes, e.g. horseradish peroxidase (HRP) and the red fluorescent protein DsRed. The effective introduction of azides was verified by mass spectrometry, after which the azido-proteins were used in Cu(I)-catalyzed [3 + 2] cycloaddition reactions. Azido-HRP retained its catalytic activity after conjugation of a small molecule. This modified protein could also be successfully immobilized on the surface of an acetylene-covered polymersome. Azido-DsRed was coupled to an acetylene-bearing protein allowing it to act as a fluorescent label, demonstrating the wide applicability of the diazo transfer procedure.
authors.affiliation: Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands.
authors.forename: Stijn F M
authors.initials: SF
authors.lastname: van Dongen
authors.forename: Rosalie L M
authors.initials: RL
authors.lastname: Teeuwen
authors.forename: Madhavan
authors.initials: M
authors.lastname: Nallani
authors.forename: Sander S
authors.initials: SS
authors.lastname: van Berkel
authors.forename: Jeroen J L M
authors.initials: JJ
authors.lastname: Cornelissen
authors.forename: Roeland J M
authors.initials: RJ
authors.lastname: Nolte
authors.forename: Jan C M
authors.initials: JC
authors.lastname: van Hest
mesh_terms: D001386:Azides / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000737:chemistry; D008164:Luminescent Proteins / Q000737:chemistry; D008239:Lysine / Q000737:chemistry; D015336:Molecular Probe Techniques; D011506:Proteins / Q000737:chemistry*; D014867:Water; D000097573:Red Fluorescent Protein
chemical_list: D001386:Azides; D004800:Enzymes, Immobilized; D006735:Horseradish Peroxidase; D008164:Luminescent Proteins; D008239:Lysine; D011506:Proteins; D014867:Water; D000097573:Red Fluorescent Protein