A biosynthetic route to photoclick chemistry on proteins

J Am Chem Soc. 2010 Oct 27;132(42):14812-8. doi: 10.1021/ja104350y.


Light-induced chemical reactions exist in nature, regulating many important cellular and organismal functions, e.g., photosensing in prokaryotes and vision formation in mammals. Here, we report the genetic incorporation of a photoreactive unnatural amino acid, p-(2-tetrazole)phenylalanine (p-Tpa), into myoglobin site-specifically in E. coli by evolving an orthogonal tRNA/aminoacyl-tRNA synthetase pair and the use of p-Tpa as a bioorthogonal chemical "handle" for fluorescent labeling of p-Tpa-encoded myoglobin via the photoclick reaction. Moreover, we elucidated the structural basis for the biosynthetic incorporation of p-Tpa into proteins by solving the X-ray structure of p-Tpa-specific aminoacyl-tRNA synthetase in complex with p-Tpa. The genetic encoding of this photoreactive amino acid should make it possible in the future to photoregulate protein function in living systems.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acyl-tRNA Synthetases / chemistry
  • Chromatography, High Pressure Liquid
  • Crystallography, X-Ray
  • Fluorescent Dyes / chemistry
  • Kinetics
  • Models, Molecular
  • Protein Biosynthesis*
  • Protein Conformation
  • Spectrometry, Mass, Electrospray Ionization
  • Spectrophotometry, Ultraviolet


  • Fluorescent Dyes
  • Amino Acyl-tRNA Synthetases