Molecular Basis of Maintaining an Oxidizing Environment Under Anaerobiosis by Soluble Fumarate Reductase

Nat Commun. 2018 Nov 19;9(1):4867. doi: 10.1038/s41467-018-07285-9.

Abstract

Osm1 and Frd1 are soluble fumarate reductases from yeast that are critical for allowing survival under anaerobic conditions. Although they maintain redox balance during anaerobiosis, the underlying mechanism is not understood. Here, we report the crystal structure of a eukaryotic soluble fumarate reductase, which is unique among soluble fumarate reductases as it lacks a heme domain. Structural and enzymatic analyses indicate that Osm1 has a specific binding pocket for flavin molecules, including FAD, FMN, and riboflavin, catalyzing their oxidation while reducing fumarate to succinate. Moreover, ER-resident Osm1 can transfer electrons from the Ero1 FAD cofactor to fumarate either by free FAD or by a direct interaction, allowing de novo disulfide bond formation in the absence of oxygen. We conclude that soluble eukaryotic fumarate reductases can maintain an oxidizing environment under anaerobic conditions, either by oxidizing cellular flavin cofactors or by a direct interaction with flavoenzymes such as Ero1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaerobiosis / genetics
  • Binding Sites
  • Cloning, Molecular
  • Crystallography, X-Ray
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Flavin Mononucleotide / chemistry*
  • Flavin Mononucleotide / metabolism
  • Flavin-Adenine Dinucleotide / chemistry*
  • Flavin-Adenine Dinucleotide / metabolism
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Glycoproteins / chemistry*
  • Glycoproteins / genetics
  • Glycoproteins / metabolism
  • Kinetics
  • Molecular Docking Simulation
  • Oxidation-Reduction
  • Oxidoreductases Acting on Sulfur Group Donors / chemistry*
  • Oxidoreductases Acting on Sulfur Group Donors / genetics
  • Oxidoreductases Acting on Sulfur Group Donors / metabolism
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Riboflavin / chemistry*
  • Riboflavin / metabolism
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Shewanella / enzymology
  • Shewanella / genetics
  • Substrate Specificity
  • Succinate Dehydrogenase / chemistry*
  • Succinate Dehydrogenase / genetics
  • Succinate Dehydrogenase / metabolism
  • Triazines / chemistry
  • Triazines / metabolism

Substances

  • Glycoproteins
  • OSM1 protein, S cerevisiae
  • Recombinant Proteins
  • Saccharomyces cerevisiae Proteins
  • Triazines
  • Flavin-Adenine Dinucleotide
  • Cibacron Blue F 3GA
  • Flavin Mononucleotide
  • Succinate Dehydrogenase
  • Oxidoreductases Acting on Sulfur Group Donors
  • ERO1 protein, S cerevisiae
  • Riboflavin