Porphyrin π-stacking in a heme protein scaffold tunes gas ligand affinity

J Inorg Biochem. 2013 Oct;127:7-12. doi: 10.1016/j.jinorgbio.2013.06.004. Epub 2013 Jun 15.


The role of π-stacking in controlling redox and ligand binding properties of porphyrins has been of interest for many years. The recent discovery of H-NOX domains has provided a model system to investigate the role of porphyrin π-stacking within a heme protein scaffold. Removal of a phenylalanine-porphyrin π-stack dramatically increased O2, NO, and CO affinities and caused changes in redox potential (~40mV) without any structural changes. These results suggest that small changes in redox potential affect ligand affinity and that π-stacking may provide a novel route to engineer heme protein properties for new functions.

Keywords: Bioinorganic chemistry; H-NOX; Heme proteins; Pi interactions; Porphyrins; Redox chemistry.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Carbon Dioxide / chemistry*
  • Carbon Dioxide / metabolism
  • Carbon Monoxide / chemistry*
  • Carbon Monoxide / metabolism
  • Hemeproteins / chemistry*
  • Hemeproteins / metabolism
  • Ligands
  • Models, Molecular
  • Oxidation-Reduction
  • Oxygen / chemistry*
  • Oxygen / metabolism
  • Porphyrins / chemistry*
  • Porphyrins / metabolism


  • Hemeproteins
  • Ligands
  • Porphyrins
  • Carbon Dioxide
  • Carbon Monoxide
  • Oxygen