title: Chemically Activatable Alkyne Tag for Low pH-Enhanced Molecular Labeling on Living Cells.
abstract: Stimuli-responsive "activatable" reactive tags are applicable to selective labeling of biomolecules in a defined area or environment in living systems, yielding new insights into cellular processes through molecular imaging and fishing. Here, we developed a chemically activatable alkyne tag that can be incorporated into biological molecules and labeled with azide-tagged functional molecules through the alkyne-azide cycloaddition "click" reaction after chemical activation. Formation of the alkyne tag from the precursor moiety was confirmed to proceed in physiological aqueous media and was particularly enhanced under mildly acidic pH. The tag was successfully applied to low-pH sensitive labeling of a cholesterol analogue with azide-tagged biotin on living mammalian cells. Our results provided proof of principle that the present activatable alkyne tag can be used as a tool to selectively analyze molecules of interest in low-pH regions in living systems.
authors.affiliation: Research Center for Advanced Science and Technology (RCAST), The University of Tokyo , 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Manami
authors.initials: M
authors.lastname: Ura
authors.affiliation: Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Izuta
authors.affiliation: Research Center for Advanced Science and Technology (RCAST), The University of Tokyo , 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan.|Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Akimitsu
authors.initials: A
authors.lastname: Okamoto
mesh_terms: D000480:Alkynes / Q000737:chemistry* / Q000378:metabolism*; D002470:Cell Survival; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019169:Jurkat Cells; D013194:Staining and Labeling
chemical_list: D000480:Alkynes