Non-hemolytic ClyA Protein Export System for Recombinant Production
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Solution Overview
Problem
High copy number expression plasmids in protein expression systems impose a metabolic burden on host cells, leading to reduced growth rates and increased loss of expression plasmids, which decreases protein production and stability.
Innovation Solution
The use of a protein export system that exploits endogenous export machinery, such as the Salmonella enterica serovar Typhi cytolysin A (ClyA) protein, to facilitate the export of recombinant proteins out of bacterial cells, minimizing metabolic burden and maintaining protein production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high copy number expression plasmids are used to increase protein yield, then protein production increases, but metabolic burden on host cells increases leading to reduced growth rate and plasmid stability
Solution Approach 1:
The patent extracts the harmful metabolic burden by exporting the recombinant protein out of the host cell using the ClyA hemolysin export system. This removes the accumulated protein that causes cellular stress, allowing high-level expression without sacrificing plasmid stability or host cell health.
Solution Approach 2:
The ClyA hemolysin protein serves as an intermediary export mechanism. It mediates the transport of recombinant proteins across the bacterial membrane, enabling efficient protein secretion and reducing intracellular accumulation that would otherwise harm the host cell.
2Productivity
If high copy number expression plasmids are used to increase protein yield, then protein production increases, but host cell growth rate decreases due to metabolic burden
Solution Approach 1:
The patent extracts the harmful metabolic burden by exporting the recombinant protein out of the host cell using the ClyA hemolysin export system. This removes the accumulated protein that causes cellular stress, allowing high-level expression without sacrificing host cell growth rate.
Solution Approach 2:
The export system operates continuously to remove recombinant protein as it is produced, maintaining a continuous flow that prevents metabolic burden accumulation. This allows both high protein production and sustained host cell growth to occur simultaneously.
3Productivity
If large exogenous export systems are used to export proteins, then export capacity increases, but device complexity and metabolic burden increase
Solution Approach 1:
The patent utilizes the host cell's own endogenous ClyA hemolysin export machinery rather than introducing complex exogenous export systems. The native export system is hijacked to perform the useful function of recombinant protein secretion, simplifying the overall system while maintaining high export capacity.
Solution Approach 2:
The ClyA hemolysin system performs multiple functions: it serves as both the export mechanism for recombinant proteins and maintains its natural role in bacterial physiology. This multi-functionality reduces the need for separate dedicated export systems, thereby reducing overall system complexity.
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
This approach enhances protein production by reducing the metabolic burden on host cells and maintaining protein stability, allowing for efficient export and immune response elicitation without the need for large exogenous export systems.
Implementation Method 1
The use of a protein export system that exploits endogenous export machinery, such as the Salmonella enterica serovar Typhi cytolysin A (ClyA) protein, to facilitate the export of recombinant proteins out of bacterial cells
Data Source
AI summary
The disclosure below provides a protein export system utilizing non-hemolytic variants of HlyE family member proteins for efficiently producing recombinant protein from a host cell. In a preferred embodiment, the protein export system utilizes protein export machinery endogenous to the host bacterium into which the protein export system vector is introduced.