Transglutaminase-Catalyzed Bioconjugation Using One-Pot Metal-Free Bioorthogonal Chemistry
journal contributionposted on 2017-09-12, 00:00 authored by Natalie M. Rachel, Jacynthe L. Toulouse, Joelle N. Pelletier
General approaches for controlled protein modification are increasingly sought-after in the arena of chemical biology. Here, using bioorthogonal reactions, we present combinatorial chemoenzymatic strategies to effectuate protein labeling. A total of three metal-free conjugations were simultaneously or sequentially incorporated in a one-pot format with microbial transglutaminase (MTG) to effectuate protein labeling. MTG offers the particularity of conjugating residues within a protein sequence rather than at its extremities, providing a route to labeling the native protein. The reactions are rapid and circumvent the incompatibility posed by metal catalysts. We identify the tetrazine ligation as most-reactive for this purpose, as demonstrated by the fluorescent labeling of two proteins. The Staudinger ligation and strain-promoted azide–alkyne cycloaddition are alternatives. Owing to the breadth of labels that MTG can use as a substrate, our results demonstrate the versatility of this system, with the researcher being able to combine specific protein substrates with a variety of labels.
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tetrazine ligationOne-Pot Metal-Free Bioorthogonal Chemistry General approachesStaudinger ligationmetal-free conjugationsprotein substratesprotein modificationbioorthogonal reactionsone-pot formatTransglutaminase-Catalyzed BioconjugationMTGmetal catalystscombinatorial chemoenzymatic strategiesprotein sequencechemical biology