Hydrophilic trans-Cyclooctenylated Noncanonical Amino Acids for Fast Intracellular Protein Labeling

Eszter Kozma, Ivana Nikić, Balázs R. Varga, Iker Valle Aramburu, Jun Hee Kang, Oliver T. Fackler, Edward A. Lemke, P. Kele

Research output: Contribution to journalArticle

23 Citations (Scopus)


Introduction of bioorthogonal functionalities (e.g., trans-cyclooctene-TCO) into a protein of interest by site-specific genetic encoding of non-canonical amino acids (ncAAs) creates uniquely targetable platforms for fluorescent labeling schemes in combination with tetrazine-functionalized dyes. However, fluorescent labeling of an intracellular protein is usually compromised by high background, arising from the hydrophobicity of ncAAs; this is typically compensated for by hours-long washout to remove excess ncAAs from the cellular interior. To overcome these problems, we designed, synthesized, and tested new, hydrophilic TCO-ncAAs. One derivative, DOTCO-lysine was genetically incorporated into proteins with good yield. The increased hydrophilicity shortened the excess ncAA washout time from hours to minutes, thus permitting rapid labeling and subsequent fluorescence microscopy.

Original languageEnglish
Pages (from-to)1518-1524
Number of pages7
Publication statusPublished - Aug 17 2016



  • amino acids
  • click chemistry
  • fluorescence
  • hydrophilicity
  • protein engineering

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Organic Chemistry

Cite this

Kozma, E., Nikić, I., Varga, B. R., Aramburu, I. V., Kang, J. H., Fackler, O. T., Lemke, E. A., & Kele, P. (2016). Hydrophilic trans-Cyclooctenylated Noncanonical Amino Acids for Fast Intracellular Protein Labeling. ChemBioChem, 1518-1524. https://doi.org/10.1002/cbic.201600284