The [NiFe]-hydrogenase accessory chaperones HypC and HybG of Escherichia coli are iron- and carbon dioxide-binding proteins

FEBS Lett. 2013 Aug 19;587(16):2512-6. doi: 10.1016/j.febslet.2013.06.055. Epub 2013 Jul 10.


[NiFe]-hydrogenase accessory proteins HypC and HypD form a complex that binds a Fe-(CN)₂CO moiety and CO₂. In this study two HypC homologues from Escherichia coli were purified under strictly anaerobic conditions and both contained sub-stoichiometric amounts of iron (approx. 0.3 molFe/mol HypC). Infrared spectroscopic analysis identified a signature at 2337 cm⁻¹ indicating bound CO₂. Aerobically isolated HypC lacked both Fe and CO₂. Exchange of either of the highly conserved amino acid residues Cys2 or His51 abolished both Fe- and CO₂-binding. Our results suggest that HypC delivers CO₂ bound directly to Fe for reduction to CO by HypD.

Keywords: Carbon dioxide; Hydrogenase; Infrared spectroscopy; Iron; Maturation; Metalloprotein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Dioxide / chemistry*
  • Carrier Proteins / chemistry
  • Cysteine / chemistry
  • Escherichia coli / enzymology*
  • Escherichia coli Proteins / chemistry*
  • Histidine / chemistry
  • Hydrogen Peroxide / chemistry
  • Hydrogenase / chemistry*
  • Iron / chemistry*
  • Ligands
  • Molecular Chaperones / chemistry*
  • Oxidation-Reduction
  • Oxygen / chemistry


  • Carrier Proteins
  • Escherichia coli Proteins
  • HybG protein, E coli
  • HypC protein, E coli
  • Ligands
  • Molecular Chaperones
  • Carbon Dioxide
  • Histidine
  • Hydrogen Peroxide
  • Iron
  • nickel-iron hydrogenase
  • Hydrogenase
  • Cysteine
  • Oxygen