Direct meso-alkynylation of metalloporphyrins through gold catalysis for hemoprotein engineering

Angew Chem Int Ed Engl. 2014 Mar 3;53(10):2611-4. doi: 10.1002/anie.201310145. Epub 2014 Jan 30.


A method was developed for the direct functionalization of metalloporphyrins at the methine protons (meso positions) to yield asymmetric alkynylated derivatives by using gold catalysis and hypervalent iodine reagents. This single-step procedure was applied to b-type heme and the product was incorporated into a gas-sensor heme protein. The terminal alkyne allows fluorophore labeling through copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). Hemoproteins with this type of engineered cofactor have several potential applications in labeling and imaging technologies. Additionally, the alkyne provides a handle for modulating porphyrin electron density, which affects cofactor redox potential and ligand affinity. This method will be helpful for investigating the chemistry of natural heme proteins and for designing artificial variants with altered properties and reactivities.

Keywords: H-NOX proteins; chemical biology; click chemistry; heme proteins; transition metal catalysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes / chemistry*
  • Catalysis
  • Ferrous Compounds / chemistry*
  • Gold / chemistry*
  • Metalloporphyrins / chemistry*
  • Models, Molecular
  • Molecular Conformation
  • Protein Engineering*


  • Alkynes
  • Ferrous Compounds
  • Metalloporphyrins
  • Gold