Evaluation of cell-free expression system for the production of soluble and functional human GPCR N-formyl peptide receptors

Protein Pept Lett. 2013 Nov;20(11):1272-9. doi: 10.2174/09298665113209990043.

Abstract

Human N-formyl peptide receptors (FPRs) belong to the G protein-coupled receptors (GPCRs) superfamily, the most frequently addressed drug targets in the pharmaceutical industry, and are considered to play important roles in innate immunity and host defense mechanisms. Although still a highly challenging task, the availability of soluble and functional GPCRs including FPRs in milligram quantities is essential to spur the advancement of protein-based structural and functional studies for drug discovery. In this report, the applicability of E. coli extracts-based cell-free expression system to producing soluble and active human FPRs and hence to FPRs protein-based research was evaluated, during which human FPR3 was selected as our prototype receptor. To better solubilize the freshly expressed human FPR3, a panel of different detergents (mostly nonionic detergents) were selected and evaluated in the cell-free system devoid of natural membrane. After one-step immunoaffinity purification, the secondary structure and biological function of purified FPR3 were characterized. A final yield of 0.6 mg functional human FPR3 per ml reaction volume was obtained. The demonstrated proper folding and functionality of the cell-free produced human FPR3 opens a new avenue for the fast and efficient generation of human FPRs (and even other GPCRs) for structural and functional analysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell-Free System*
  • Escherichia coli / genetics*
  • Humans
  • Protein Structure, Secondary
  • Receptors, Formyl Peptide / biosynthesis
  • Receptors, Formyl Peptide / chemistry
  • Receptors, Formyl Peptide / genetics*
  • Receptors, G-Protein-Coupled / biosynthesis*
  • Receptors, G-Protein-Coupled / genetics
  • Structure-Activity Relationship

Substances

  • FPR3 protein, human
  • Receptors, Formyl Peptide
  • Receptors, G-Protein-Coupled