Site-Specific Labeling of Proteins Using Unnatural Amino Acids

  • Lee, Kyung Jin (Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST)) ;
  • Kang, Deokhee (Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST)) ;
  • Park, Hee-Sung (Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST))
  • Received : 2019.04.15
  • Accepted : 2019.05.02
  • Published : 2019.05.31


Labeling of a protein with a specific dye or tag at defined positions is a critical step in tracing the subtle behavior of the protein and assessing its cellular function. Over the last decade, many strategies have been developed to achieve selective labeling of proteins in living cells. In particular, the site-specific unnatural amino acid (UAA) incorporation technique has gained increasing attention since it enables attachment of various organic probes to a specific position of a protein in a more precise way. In this review, we describe how the UAA incorporation technique has expanded our ability to achieve site-specific labeling and visualization of target proteins for functional analyses in live cells.

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Fig. 1. Unnatural amino acids used for site-specific protein labeling.

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Fig. 2. Bioorthogonal reactions for labeling of a protein of interest.

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Fig. 3. Promising applications of UAA-based protein-labeling scheme.

Table 1. Unnatural amino acids and bioorthogonal conjugation schemes

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Supported by : National Research Foundation of Korea, Samsung Science & Technology Foundation


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