Cytochrome c oxidase assembly factors with a thioredoxin fold are conserved among prokaryotes and eukaryotes

J Mol Med (Berl). 2000;78(5):239-42. doi: 10.1007/s001090000110.


Cytochrome c oxidase (COX) is a multi-subunit terminal oxidase of the eukaryotic respiratory chain involved in the reduction of oxygen to water. Numerous lines of evidence suggest that the assembly of COX is a multi-step, assisted process that depends on several assembly factors with largely unknown functions. Sco1/2 proteins have been isolated as high-copy number suppressors of a deletion of copper chaperone Cox 17, implicating Sco1/2 in copper transport to COX subunits I or II. Here I report the similarity of Sco1/2 assembly factors to peroxiredoxins and thiol:disulfide oxidoreductases with a thioredoxin fold, suggesting that Sco-related proteins perform a catalytic rather than a copper transport function. Reported sequence similarities, together with the functional role of bacterial Sco-related proteins suggest that Sco-related proteins represent a new class of membrane-anchored thiol:disulfide oxidoreductases involved in COX maturation.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism
  • Carrier Proteins
  • Cation Transport Proteins*
  • Conserved Sequence
  • Electron Transport Complex IV / metabolism*
  • Humans
  • Membrane Proteins / chemistry*
  • Membrane Proteins / metabolism*
  • Mitochondrial Proteins
  • Molecular Sequence Data
  • Protein Folding
  • Proteins / chemistry
  • Proteins / metabolism
  • Thioredoxins / chemistry*


  • Bacterial Proteins
  • COX17 protein, human
  • Carrier Proteins
  • Cation Transport Proteins
  • Membrane Proteins
  • Mitochondrial Proteins
  • Proteins
  • SCO1 protein, human
  • SCO2 protein, human
  • Thioredoxins
  • Electron Transport Complex IV