Recombinant production of rhesus θ-defensin-1 (RTD-1) using a bacterial expression system

Mol Biosyst. 2012 Apr;8(4):1359-65. doi: 10.1039/c2mb05451e. Epub 2012 Feb 10.

Abstract

Defensins are antimicrobial peptides that are important in the innate immune defense of mammals. In contrast to mammalian α- and β-defensins, rhesus θ-defensin-1 (RTD-1) comprises only 18 amino acids stabilized by three disulfide bonds and an unusual backbone cyclic topology. In this work we report for the first time the recombinant expression of the fully folded θ-defensin RTD-1 using a bacterial expression system. This was accomplished using an intramolecular native chemical ligation in combination with a modified protein-splicing unit. RTD-1 was produced either in vitro or in vivo. In-cell production of RTD-1 was estimated to reach an intracellular concentration of ~4 μM. Recombinant RTD-1 was shown to be correctly folded as characterized by heteronuclear-NMR and by its ability to specifically inhibit lethal factor protease. The recombinant production of folded θ-defensins opens the possibility to produce peptide libraries based on this peptide scaffold that could be used to develop in-cell screening and directed evolution technologies.

Publication types

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

MeSH terms

  • Amino Acids / chemistry
  • Animals
  • Cloning, Molecular
  • Defensins / biosynthesis*
  • Defensins / genetics
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Gene Expression Regulation, Bacterial
  • Macaca mulatta
  • Nuclear Magnetic Resonance, Biomolecular / methods
  • Peptides, Cyclic / biosynthesis*
  • Peptides, Cyclic / genetics
  • Recombinant Proteins / biosynthesis*
  • Recombinant Proteins / genetics

Substances

  • Amino Acids
  • Defensins
  • Peptides, Cyclic
  • Recombinant Proteins