E. coli lpp Mutation for High-Yield Protein Secretion
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Solution Overview
Problem
Current methods for producing recombinant proteins in E. coli, especially for secreting heterologous proteins into the fermentation medium, face challenges such as low yields, complex and costly production processes, and the need for post-treatment to correct misfolding, making them inefficient for industrial-scale production.
Innovation Solution
Utilizing E. coli strains with lpp mutations that allow for high-yield secretion of correctly folded heterologous proteins into the fermentation medium, leveraging the Sec system for protein transport and employing defined salt media for robust growth and secretion, enabling direct purification from the medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional E. coli strains are used for protein secretion into fermentation medium, then production process is simpler, but yields are low and proteins are misfolded
Solution Approach 1:
The patent modifies specific genetic parameters of E. coli strains by introducing mutations in the lpp gene (encoding lipoprotein) to alter membrane properties. This parameter change enables high-yield protein secretion (up to 500 mg/l) while maintaining correct protein folding, resolving the contradiction between productivity and proper protein conformation.
Solution Approach 2:
The patent uses defined salt media instead of expensive complex media for fermentation. This disposable, inexpensive medium supports robust growth of the modified E. coli strains and enables high-yield protein production without requiring costly supplements, making the process economically viable.
2Productivity
If proteins are produced intracellularly in E. coli, then production efficiency is high, but purification is difficult and proteins are misfolded
Solution Approach 1:
The patent extracts the protein secretion function from the intracellular compartment to the extracellular fermentation medium by modifying E. coli strains with lpp mutations. This extraction enables proteins to be secreted into the medium in correct folded form, maintaining high production efficiency while eliminating misfolding problems associated with intracellular production.
3Reliability
If complex media are used for E. coli growth, then cell growth is robust, but production costs increase
Solution Approach 1:
The patent replaces expensive complex media with inexpensive defined salt media for E. coli cultivation. The modified E. coli strains with lpp mutations exhibit robust growth and high protein secretion yields in this simple medium, significantly reducing production costs while maintaining reliability.
4Manufacturing precision
If multiple purification stages are used, then protein purity is high, but purification costs and time increase
Solution Approach 1:
The patent extracts proteins directly into the fermentation medium in correct folded form, simplifying the purification process. Since proteins are secreted in the periplasmic oxidation state with correct disulfide bridges already formed, fewer purification stages are needed compared to intracellular production, reducing both time and cost while maintaining high purity.
Solution Approach 2:
The lpp mutations change the physiological parameters of E. coli to enable constitutive protein secretion into the medium. This parameter change eliminates the need for cell disruption and simplifies downstream processing, reducing purification time and costs while achieving high protein purity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Achieves high-yield production of correctly folded heterologous proteins, including antibodies and other eukaryotic proteins, with extracellular yields exceeding 500 mg/l, simplifying the production process and reducing purification costs by allowing direct purification from the fermentation medium.
Implementation Method 1
E. coli has various systems to transport proteins across the cytoplasmic membrane into the periplasm. The Sec system is most commonly used for the secretory production of recombinant proteins. In the case of the Sec system, the proteins are transported through the cytoplasmic membrane in the unfolded state
Implementation Method 2
the formation of any necessary disulfide bridges is made possible under the oxidative conditions and by the chaperones of the periplasm
Implementation Method 3
Utilizing E. coli strains with lpp mutations that allow for high-yield secretion of correctly folded heterologous proteins into the fermentation medium
Implementation Method 4
Process for the fermentative production of heterologous proteins using an Escherichia coli strain with a lipoprotein mutation
Data Source
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AI summary
Producing a heterologous protein (I) comprises culturing an Escherichia colistrain on a technical scale in a fermentation medium containing more than 4 mg/l calcium ions or more than 48 mg/l magnesium ions, whereby (I) is secreted into the medium, and separating (I) from the medium. The Escherichia colistrain has a mutation in the lpp gene or its promoter and comprises a (I)-encoding protein linked to a signal sequence encoding a signal peptide.