Protease-Deficient Bacterial Hosts for Stable Protein Expression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current bacterial expression systems, such as those derived from Escherichia coli, often result in low protein yields or unstable proteins due to energy-dependent degradation by ATP-dependent proteases like Clp and Lon proteases.
Innovation Solution
Engineering bacteria to be deficient in proteases such as ClpP, ClpQ, Lon, and OmpT, thereby increasing protein expression levels by disrupting these proteases or reducing their activity through genetic modifications, including deletions and mutations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bacterial expression systems are used for protein production, then fast growth kinetics and high cell density are achieved, but protein yields are low and proteins are unstable due to degradation by ATP-dependent proteases
Solution Approach 1:
The invention extracts and removes the harmful proteolytic activity from the bacterial expression system by deleting or inactivating specific protease genes (lon, clpP, clpX, ompT). This eliminates the degradation pathway while preserving the beneficial fast growth and high cell density characteristics of E. coli, thereby improving both protein yield and stability.
Solution Approach 2:
The invention converts the harmful protease activity into a benefit by using targeted gene deletions to create a strain that is specifically deficient in proteases known to degrade recombinant proteins. The controlled creation of protease deficiency transforms the natural protein degradation problem into a controlled system that protects recombinant proteins while maintaining bacterial viability and growth.
2Reliability
If protease activity is increased to maintain cellular protein homeostasis, then cellular health is maintained, but recombinant protein expression levels decrease due to degradation
Solution Approach 1:
The invention applies local quality by creating a spatial and functional distinction between cellular protein handling and recombinant protein stability. Specific proteases are selectively deleted to protect recombinant proteins while the bacterial cell maintains adequate proteolytic activity for essential cellular functions through remaining protease systems, thus preserving cellular health while enhancing recombinant protein expression.
3Productivity
If multiple protease genes are deleted to maximize protein stability, then protein yields increase significantly, but bacterial fitness and growth may be compromised
Solution Approach 1:
The invention applies partial action by selectively deleting only the most impactful protease genes (lon, clpP, clpX, ompT) rather than eliminating all proteolytic activity. This partial deletion strategy achieves sufficient protection of recombinant proteins to dramatically improve yields while preserving enough protease function to maintain bacterial growth and fitness, avoiding the extreme of complete protease elimination.
Data Source
AI summary
The present disclosure provides host cells for reliable, high yield recombinant protein production, including unstable proteins. The present host cell (e.g., a bacterial cell) is deficient in at least one protease (or a subunit of a protease) such as Clp or ClpP. The host cell may also contain an expression vector that encodes a protein or polypeptide for overexpression.