Optimization of culture conditions for the expression of three different insoluble proteins in Escherichia coli

Sci Rep. 2019 Nov 14;9(1):16850. doi: 10.1038/s41598-019-53200-7.

Abstract

Recombinant protein expression for structural and therapeutic applications requires the use of systems with high expression yields. Escherichia coli is considered the workhorse for this purpose, given its fast growth rate and feasible manipulation. However, bacterial inclusion body formation remains a challenge for further protein purification. We analyzed and optimized the expression conditions for three different proteins: an anti-MICA scFv, MICA, and p19 subunit of IL-23. We used a response surface methodology based on a three-level Box-Behnken design, which included three factors: post-induction temperature, post-induction time and IPTG concentration. Comparing this information with soluble protein data in a principal component analysis revealed that insoluble and soluble proteins have different optimal conditions for post-induction temperature, post-induction time, IPTG concentration and in amino acid sequence features. Finally, we optimized the refolding conditions of the least expressed protein, anti-MICA scFv, using a fast dilution protocol with different additives, obtaining soluble and active scFv for binding assays. These results allowed us to obtain higher yields of proteins expressed in inclusion bodies. Further studies using the system proposed in this study may lead to the identification of optimal environmental factors for a given protein sequence, favoring the acceleration of bioprocess development and structural studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cloning, Molecular / methods*
  • Escherichia coli / drug effects
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Factor Analysis, Statistical
  • Gene Expression / drug effects
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Histocompatibility Antigens Class I / chemistry
  • Histocompatibility Antigens Class I / genetics*
  • Histocompatibility Antigens Class I / isolation & purification
  • Humans
  • Inclusion Bodies / chemistry
  • Interleukin-23 / chemistry
  • Interleukin-23 / genetics*
  • Interleukin-23 / isolation & purification
  • Isopropyl Thiogalactoside / pharmacology
  • Principal Component Analysis
  • Protein Refolding
  • Protein Subunits / chemistry
  • Protein Subunits / genetics
  • Protein Subunits / isolation & purification
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / isolation & purification
  • Single-Chain Antibodies / chemistry
  • Single-Chain Antibodies / genetics*
  • Single-Chain Antibodies / isolation & purification
  • Solubility

Substances

  • Histocompatibility Antigens Class I
  • Interleukin-23
  • MHC class I-related chain A
  • Protein Subunits
  • Recombinant Proteins
  • Single-Chain Antibodies
  • Isopropyl Thiogalactoside