The quiescin sulfhydryl oxidase (hQSOX1b) tunes the expression of resistin-like molecule alpha (RELM-α or mFIZZ1) in a wheat germ cell-free extract

PLoS One. 2013;8(1):e55621. doi: 10.1371/journal.pone.0055621. Epub 2013 Jan 31.


Background: Although disulfide bond formation in proteins is one of the most common types of post-translational modifications, the production of recombinant disulfide-rich proteins remains a challenge. The most popular host for recombinant protein production is Escherichia coli, but disulfide-rich proteins are here often misfolded, degraded, or found in inclusion bodies.

Methodology/principal findings: We optimize an in vitro wheat germ translation system for the expression of an immunological important eukaryotic protein that has to form five disulfide bonds, resistin-like alpha (mFIZZ1). Expression in combination with human quiescin sulfhydryl oxidase (hQSOX1b), the disulfide bond-forming enzyme of the endoplasmic reticulum, results in soluble, intramolecular disulfide bonded, monomeric, and biological active protein. The mFIZZ1 protein clearly suppresses the production of the cytokines IL-5 and IL-13 in mouse splenocytes cultured under Th2 permissive conditions.

Conclusion/significance: The quiescin sulfhydryl oxidase hQSOX1b seems to function as a chaperone and oxidase during the oxidative folding. This example for mFIZZ1 should encourage the design of an appropriate thiol/disulfide oxidoreductase-tuned cell free expression system for other challenging disulfide rich proteins.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Disulfides
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression Regulation*
  • Germ Cells / metabolism*
  • Humans
  • Intercellular Signaling Peptides and Proteins / chemistry
  • Intercellular Signaling Peptides and Proteins / genetics*
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Mice
  • Molecular Sequence Data
  • Oxidation-Reduction
  • Oxidoreductases Acting on Sulfur Group Donors / genetics
  • Oxidoreductases Acting on Sulfur Group Donors / metabolism*
  • Protein Folding
  • Protein Structure, Secondary
  • Sequence Alignment
  • Solubility
  • Triticum / genetics*
  • Triticum / metabolism


  • Disulfides
  • Intercellular Signaling Peptides and Proteins
  • Retnla protein, mouse
  • Oxidoreductases Acting on Sulfur Group Donors
  • QSOX1 protein, human