Efficient recovery of recombinant CRM197 expressed as inclusion bodies in E.coli

PLoS One. 2018 Jul 18;13(7):e0201060. doi: 10.1371/journal.pone.0201060. eCollection 2018.

Abstract

CRM197, which retains the same inflammatory and immune-stimulant properties as diphtheria toxin but with reduced toxicity, has been used as a safe carrier in conjugated vaccines. Expression of recombinant CRM197 in E. coli is limited due to formation of inclusion bodies. Soluble expression attempts in Bacillus subtilis, P. fluorescens, Pichia pastoris, and E. coli were partially unsuccessful or did not generate yields sufficient for industrial scale production. Multiple approaches have been attempted to produce CRM197 in E. coli, which has attractive features such as high yield, simplicity, fast growth, etc., including expression of oxidative host, concurrent expression of chaperones, or periplasmic export. Recently, alternative methods for recovery of insoluble proteins expressed in E. coli were reported. Compared to traditional denaturation/refolding, these methods used the non-denaturing solubilization agent, N-lauroylsarkosine to obtain higher recovery yields of native proteins. Based on this work, here, we focused on solubilization of CRM197 from E. coli inclusion bodies. First, CRM197 was expressed as inclusion bodies by high-level expression of recombinant CRM197 in E. coli (126.8 mg/g dcw). Then bioactive CRM197 was isolated from these inclusion bodies with high yield (108.1 mg/g dcw) through solubilization with N-lauroylsarkosine including Triton X-100 and CHAPS, and purified by Ni-affinity chromatography and size-exclusion chromatography. In this study, we present a cost-effective alternative for the production of bioactive CRM197 and compare our recovery yield with yields in other production processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism*
  • Cloning, Molecular
  • Escherichia coli / cytology*
  • Escherichia coli / genetics*
  • Gene Expression
  • Inclusion Bodies / genetics*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics*
  • Recombinant Proteins / metabolism*
  • Solubility

Substances

  • Bacterial Proteins
  • Recombinant Proteins
  • CRM197 (non-toxic variant of diphtheria toxin)

Grants and funding

The author(s) received no specific funding for this work ForBioKorea Co., Ltd provided support in the form of salaries for authors [HL, AP, SJ, JK, YP, BK], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the 'author contributions' section.