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Addition of Repressor in inducible promoter system improves soluble expression of recombinant protein in E. coli
Microbial Cell Factories volume 5, Article number: P19 (2006)
Insoluble protein aggregate (inclusion body) is frequently accumulated during the heterologous protein expression by the bacterial inducible promoter system. In this study, although many reports have proposed the methodology to circumvent the aggregate formation [1–3], we tried to control the transcription rate by an addition of the repressor for inducible promoter. The addition of repressor was tried just after the inducer was added, in order to increase the soluble expression level.
To improve the soluble expression level of recombinant interferon-alpha (IFN-alpha) in E. coli, repressor (glucose) was added after induction. In this system, arabinose-inducible promoter (pBAD) controlled the transcription of IFN-alpha gene. The fractionation of soluble and insoluble part of the induced E. coli by B-PERII solution (Pierce) showed that glucose addition after induction resulted in improvement of the soluble expression, otherwise IFN-alpha was expressed mostly in insoluble portion (see Figure 1). Finally, over 60% of the total protein expression was found in the soluble fraction of total cell lysate. Probably this principle might be able to apply to other heterologous protein expression which is prone to a protein aggregate formation in the cytoplasm.
The glucose (repressor) addition improved the soluble expression level in arabinose-inducible promoter system in E. coli.
This principle might be able to apply to a heterologous protein expression which is prone to a protein aggregate formation in the cytoplasm.
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Sorensen HP, Mortensen KK: Soluble expression of recombinant protein in the cytoplasm of Escherichia coli . Microb Cell Fact. 2005, 4: 1-. 10.1186/1475-2859-4-1.
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Jung, K. Addition of Repressor in inducible promoter system improves soluble expression of recombinant protein in E. coli. Microb Cell Fact 5, P19 (2006) doi:10.1186/1475-2859-5-S1-P19
- Inclusion Body
- Protein Aggregate
- Transcription Rate
- Inducible Promoter
- Insoluble Protein