N-terminal modification of proteins with o-aminophenols

J Am Chem Soc. 2014 Jul 9;136(27):9572-9. doi: 10.1021/ja500728c. Epub 2014 Jun 25.

Abstract

The synthetic modification of proteins plays an important role in chemical biology and biomaterials science. These fields provide a constant need for chemical tools that can introduce new functionality in specific locations on protein surfaces. In this work, an oxidative strategy is demonstrated for the efficient modification of N-terminal residues on peptides and N-terminal proline residues on proteins. The strategy uses o-aminophenols or o-catechols that are oxidized to active coupling species in situ using potassium ferricyanide. Peptide screening results have revealed that many N-terminal amino acids can participate in this reaction, and that proline residues are particularly reactive. When applied to protein substrates, the reaction shows a stronger requirement for the proline group. Key advantages of the reaction include its fast second-order kinetics and ability to achieve site-selective modification in a single step using low concentrations of reagent. Although free cysteines are also modified by the coupling reaction, they can be protected through disulfide formation and then liberated after N-terminal coupling is complete. This allows access to doubly functionalized bioconjugates that can be difficult to access using other methods.

Publication types

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

MeSH terms

  • Aminophenols / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Oxidation-Reduction
  • Peptides / chemistry
  • Proline / chemistry*
  • Proteins / chemistry*

Substances

  • Aminophenols
  • Peptides
  • Proteins
  • 2-aminophenol
  • Proline