Recombinant E. coli Strain with DsbC and Reduced Tsp Activity
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Solution Overview
Problem
Current bacterial strains used for producing recombinant proteins, such as E. coli, face limitations including poor cell health phenotype and proteolytic degradation of proteins of interest due to high Tsp protease activity, which affects protein yield and stability.
Innovation Solution
A recombinant gram-negative bacterial cell strain with reduced Tsp protein activity and expression of DsbC, a disulfide bond catalyst, to enhance protein production and cell health, along with specific mutations in the spr gene to suppress thermosensitive growth and proteolytic degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bacterial cells (E. coli) are used for producing recombinant proteins, then production versatility and gene insertion capability are improved, but cell health phenotype deteriorates
Solution Approach 1:
The patent modifies the bacterial host strain by introducing specific genetic modifications including overexpression of DsbC (a disulfide bond catalyst) and reduction of Tsp protease activity. These parameter changes in the cellular environment improve protein folding efficiency and reduce degradation, thereby enhancing cell health and productivity while maintaining the versatility of E. coli as a production platform
Solution Approach 2:
The patent introduces DsbC as an intermediary molecule that facilitates proper disulfide bond formation in the periplasm. This mediator protein improves the cellular environment for recombinant protein production, enabling better cell health and protein stability without compromising the inherent versatility of E. coli host cells
2Productivity
If Tsp protease activity is high in bacterial cells, then protein turnover is enhanced, but proteolytic degradation of proteins of interest increases
Solution Approach 1:
The patent reduces Tsp protease activity to convert the harmful effect of excessive proteolytic degradation into a beneficial outcome. By lowering Tsp activity, the system maintains sufficient protein turnover while preventing degradation of recombinant proteins, thereby transforming a harmful factor into a controllable parameter that supports product stability
3Productivity
If protein yield is increased through recombinant expression, then productivity improves, but proteolytic degradation increases
Solution Approach 1:
The patent changes the cellular parameter profile by overexpressing DsbC and reducing Tsp protease activity. These parameter modifications create an optimized environment where high protein yield can be achieved without proportionally increasing proteolytic degradation, as the modified cellular conditions protect recombinant proteins from degradation
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
The strain exhibits improved growth rates, increased protein yield, and reduced proteolytic degradation, leading to higher viability and productivity of recombinant proteins like antibodies binding to CD154, with enhanced stability and efficiency in protein production.
Implementation Method 1
DsbC, a disulfide bond catalyst
Data Source
AI summary
The present invention provides a recombinant gram-negative bacterial cell comprising an expression vector comprising a recombinant polynucleotide encoding DsbC and one or more polynucleotides encoding an antibody or an antigen-binding fragment thereof specifically binding to CD154.