Functional expression of an scFv on bacterial magnetic particles by in vitro docking

Biochem Biophys Res Commun. 2014 Feb 28;445(1):1-5. doi: 10.1016/j.bbrc.2013.12.102. Epub 2014 Jan 25.


A Gram-negative, magnetotactic bacterium, Magnetospirillum magneticum AMB-1 produces nano-sized magnetic particles (BacMPs) in the cytoplasm. Although various applications of genetically engineered BacMPs have been demonstrated, such as immunoassay, ligand-receptor interaction or cell separation, by expressing a target protein on BacMPs, it has been difficult to express disulfide-bonded proteins on BacMPs due to lack of disulfide-bond formation in the cytoplasm. Here, we propose a novel dual expression system, called in vitro docking, of a disulfide-bonded protein on BacMPs by directing an immunoglobulin Fc-fused target protein to the periplasm and its docking protein ZZ on BacMPs. By in vitro docking, an scFv-Fc fusion protein was functionally expressed on BacMPs in the dimeric or trimeric form. Our novel disulfide-bonded protein expression system on BacMPs will be useful for efficient screening of potential ligands or drugs, analyzing ligand-receptor interactions or as a magnetic carrier for affinity purification.

Keywords: Bacterial magnetic particles (BacMPs); Immunoglobulin Fc; In vitro docking; Magnetospirillum magneticum AMB-1; Single chain variable fragment (scFv).

MeSH terms

  • Blotting, Western
  • Disulfides / metabolism
  • Ferrosoferric Oxide / metabolism*
  • Magnetosomes / metabolism*
  • Magnetospirillum / genetics
  • Magnetospirillum / metabolism*
  • Nanoparticles / metabolism
  • Protein Binding
  • Recombinant Proteins / metabolism
  • Single-Chain Antibodies / genetics
  • Single-Chain Antibodies / metabolism*


  • Disulfides
  • Recombinant Proteins
  • Single-Chain Antibodies
  • Ferrosoferric Oxide