Sulphur shuttling across a chaperone during molybdenum cofactor maturation

Nat Commun. 2015 Feb 4:6:6148. doi: 10.1038/ncomms7148.

Abstract

Formate dehydrogenases (FDHs) are of interest as they are natural catalysts that sequester atmospheric CO2, generating reduced carbon compounds with possible uses as fuel. FDHs activity in Escherichia coli strictly requires the sulphurtransferase EcFdhD, which likely transfers sulphur from IscS to the molybdenum cofactor (Mo-bisPGD) of FDHs. Here we show that EcFdhD binds Mo-bisPGD in vivo and has submicromolar affinity for GDP-used as a surrogate of the molybdenum cofactor's nucleotide moieties. The crystal structure of EcFdhD in complex with GDP shows two symmetrical binding sites located on the same face of the dimer. These binding sites are connected via a tunnel-like cavity to the opposite face of the dimer where two dynamic loops, each harbouring two functionally important cysteine residues, are present. On the basis of structure-guided mutagenesis, we propose a model for the sulphuration mechanism of Mo-bisPGD where the sulphur atom shuttles across the chaperone dimer.

MeSH terms

  • Binding Sites
  • Biocatalysis
  • Carbon Cycle
  • Carbon Dioxide / metabolism
  • Carbon-Sulfur Lyases / metabolism
  • Cloning, Molecular
  • Coenzymes / chemistry*
  • Coenzymes / metabolism
  • Crystallography, X-Ray
  • Escherichia coli / chemistry
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Formate Dehydrogenases / chemistry*
  • Formate Dehydrogenases / genetics
  • Formate Dehydrogenases / metabolism
  • Formates / chemistry
  • Formates / metabolism
  • Gene Expression
  • Guanosine Diphosphate / chemistry*
  • Guanosine Diphosphate / metabolism
  • Hydrogenase / chemistry*
  • Hydrogenase / genetics
  • Hydrogenase / metabolism
  • Models, Molecular
  • Molecular Chaperones / chemistry*
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism
  • Molybdenum / chemistry*
  • Molybdenum / metabolism
  • Multienzyme Complexes / chemistry*
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / metabolism
  • Oxidation-Reduction
  • Plasmids / chemistry
  • Plasmids / metabolism
  • Protein Binding
  • Protein Multimerization
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sulfur / chemistry
  • Sulfur / metabolism

Substances

  • Coenzymes
  • Formates
  • Molecular Chaperones
  • Multienzyme Complexes
  • formic acid
  • Carbon Dioxide
  • Guanosine Diphosphate
  • Sulfur
  • Molybdenum
  • Hydrogenase
  • Formate Dehydrogenases
  • formate hydrogenlyase
  • Carbon-Sulfur Lyases
  • cysteine desulfurase