Engineered Host Cells for Membrane Protein Expression
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Solution Overview
Problem
Current methods face challenges in achieving high-level expression and correct orientation of membrane proteins in foreign host cells, leading to low yields and stability issues, which hinders structural and functional characterization and drug discovery efforts targeting membrane proteins.
Innovation Solution
A host cell system is developed, specifically engineered with mutations in exogenous nucleic acid molecules encoding membrane proteins like VKORc1 and host cell-specific mutations in genes such as dsbB, yidC, and ubiquinone biosynthesis genes, to enhance expression and functionality of membrane proteins in E. coli.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If membrane proteins are overexpressed in foreign host cells using conventional methods, then expression levels are increased, but mis-targeting and inclusion body formation occur leading to protein degradation or cell death
Solution Approach 1:
The patent applies parameter changes by modifying host cell genetic parameters (mutations in disulfide bond enzymes, insertases, ubiquinone biosynthesis genes, and cytoplasmic proteases) to create an optimized expression environment. These parameter changes in the host cell system enable high-level membrane protein expression while preventing mis-targeting and inclusion body formation, thereby maintaining protein stability and functionality.
2Productivity
If membrane proteins are overexpressed in foreign host cells, then more protein is produced, but correct orientation and assembly become more difficult to achieve
Solution Approach 1:
The patent modifies host cell parameters by introducing specific mutations in genes encoding membrane insertion machinery components (insertases like YidC) and disulfide bond enzymes. These parameter changes in the host cell system facilitate correct membrane protein orientation and assembly during high-level expression, ensuring that topogenic signals are properly recognized and processed despite increased expression demands.
3Ease of manufacture
If conventional expression systems are used for membrane proteins, then standard protocols can be applied, but conformational stability and functionality are compromised
Solution Approach 1:
The patent employs self-service by engineering the host cell system itself to provide the necessary conditions for membrane protein stability. Through mutations in disulfide bond enzymes and other host cell components, the system automatically ensures correct disulfide bond formation, proper folding, and conformational stability of expressed membrane proteins, eliminating the need for external stabilization measures while maintaining standardizable protocols.
Data Source
AI summary
Provided herein are host cells or host cellular expression systems that express a membrane protein. Also, methods are provided that use such host cells or host cellular expression systems to produce higher amounts of the membrane proteins. Further, the cells or cellular systems can be used as tools for the functional characterization of membrane proteins, as well as for screening and drug discovery efforts targeting membrane proteins.