Functional reconstitution of mitochondrial Fe/S cluster synthesis on Isu1 reveals the involvement of ferredoxin

Nat Commun. 2014 Oct 31;5:5013. doi: 10.1038/ncomms6013.

Abstract

Maturation of iron-sulphur (Fe/S) proteins involves complex biosynthetic machinery. In vivo synthesis of [2Fe-2S] clusters on the mitochondrial scaffold protein Isu1 requires the cysteine desulphurase complex Nfs1-Isd11, frataxin, ferredoxin Yah1 and its reductase Arh1. The roles of Yah1-Arh1 have remained enigmatic, because they are not required for in vitro Fe/S cluster assembly. Here, we reconstitute [2Fe-2S] cluster synthesis on Isu1 in a reaction depending on Nfs1-Isd11, frataxin, Yah1, Arh1 and NADPH. Unlike in the bacterial system, frataxin is an essential part of Fe/S cluster biosynthesis and is required simultaneously and stoichiometrically to Yah1. Reduced but not oxidized Yah1 tightly interacts with apo-Isu1 indicating a dynamic interaction between Yah1-apo-Isu1. Nuclear magnetic resonance structural studies identify the Yah1-apo-Isu1 interaction surface and suggest a pathway for electron flow from reduced ferredoxin to Isu1. Together, our study defines the molecular function of the ferredoxin Yah1 and its human orthologue FDX2 in mitochondrial Fe/S cluster synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenodoxin / chemistry
  • Adrenodoxin / metabolism*
  • Biocatalysis
  • Chaetomium
  • Escherichia coli
  • Ferredoxin-NADP Reductase / metabolism
  • Ferredoxins / metabolism
  • Humans
  • Iron-Sulfur Proteins / biosynthesis*
  • Membrane Proteins / metabolism
  • Mitochondria / metabolism
  • Mitochondrial Proteins / chemistry
  • Mitochondrial Proteins / metabolism*
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Sulfurtransferases / metabolism

Substances

  • Ferredoxins
  • ISU1 protein, S cerevisiae
  • Iron-Sulfur Proteins
  • Isd11 protein, S cerevisiae
  • Membrane Proteins
  • Mitochondrial Proteins
  • Saccharomyces cerevisiae Proteins
  • YAH1 protein, S cerevisiae
  • Adrenodoxin
  • Arh1 protein, S cerevisiae
  • Ferredoxin-NADP Reductase
  • Sulfurtransferases
  • NFS1 protein, S cerevisiae

Associated data

  • PDB/2MJD
  • PDB/2MJE