A general method for the covalent labeling of fusion proteins with small molecules in vivo

Nat Biotechnol. 2003 Jan;21(1):86-9. doi: 10.1038/nbt765. Epub 2002 Dec 9.


Characterizing the movement, interactions, and chemical microenvironment of a protein inside the living cell is crucial to a detailed understanding of its function. Most strategies aimed at realizing this objective are based on genetically fusing the protein of interest to a reporter protein that monitors changes in the environment of the coupled protein. Examples include fusions with fluorescent proteins, the yeast two-hybrid system, and split ubiquitin. However, these techniques have various limitations, and considerable effort is being devoted to specific labeling of proteins in vivo with small synthetic molecules capable of probing and modulating their function. These approaches are currently based on the noncovalent binding of a small molecule to a protein, the formation of stable complexes between biarsenical compounds and peptides containing cysteines, or the use of biotin acceptor domains. Here we describe a general method for the covalent labeling of fusion proteins in vivo that complements existing methods for noncovalent labeling of proteins and that may open up new ways of studying proteins in living cells.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Technical Report
  • Validation Study

MeSH terms

  • Animals
  • Biotin / chemistry
  • Biotin / metabolism
  • CHO Cells / chemistry
  • CHO Cells / cytology
  • CHO Cells / metabolism
  • Cricetinae
  • Escherichia coli / chemistry
  • Escherichia coli / cytology
  • Escherichia coli / metabolism
  • Fluorescein / chemistry
  • Fluorescein / metabolism
  • Humans
  • Ligands
  • Macromolecular Substances
  • Microscopy, Confocal / methods
  • Microscopy, Fluorescence / methods
  • Molecular Weight
  • O(6)-Methylguanine-DNA Methyltransferase / chemistry
  • O(6)-Methylguanine-DNA Methyltransferase / metabolism*
  • Protein Binding*
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism*
  • Staining and Labeling / methods*
  • Yeasts / chemistry
  • Yeasts / cytology
  • Yeasts / metabolism


  • Ligands
  • Macromolecular Substances
  • Recombinant Fusion Proteins
  • Biotin
  • O(6)-Methylguanine-DNA Methyltransferase
  • Fluorescein