PhoS Gene Mutation for Corynebacterium Protein Secretion
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Solution Overview
Problem
Current methods for secretory production of heterologous proteins by coryneform bacteria are limited in efficiency, and there is a lack of understanding regarding the relationship between the PhoRS system and secretory production, as well as the effectiveness of specific mutations in the PhoS protein for improving this process.
Innovation Solution
Modifying coryneform bacteria to harbor a phoS gene with specific mutations, such as replacing the tryptophan residue at position 302 with lysine, alanine, valine, serine, cysteine, methionine, aspartic acid, or asparagine, to enhance secretory production of heterologous proteins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional secretory production methods are used in coryneform bacteria, then protein secretion occurs through existing pathways, but the accumulation amount of secreted protein is limited
Solution Approach 1:
The patent applies parameter changes by mutating specific amino acid residues in the PhoS protein (sensor kinase) to alter its phosphorylation characteristics. The mutation changes the phosphorylation state of PhoS, which in turn modifies the expression levels of downstream genes including those involved in protein secretion pathways, thereby increasing the accumulation amount of secreted heterologous proteins
Solution Approach 2:
The patent utilizes the two-component regulatory system (PhoS-PhoR) as a feedback mechanism. The sensor kinase PhoS detects environmental signals and undergoes autophosphorylation, then transfers the phosphate group to response regulator PhoR, which regulates gene expression. By mutating PhoS, the patent modifies this feedback loop to enhance secretory production
2Productivity
If the activity of cell surface layer proteins is reduced to improve secretory production, then secretion efficiency increases, but the mechanism is not fully understood
Solution Approach 1:
The patent introduces the PhoS protein as an intermediary element that mediates between environmental signals and gene expression. By mutating PhoS, the patent creates a controllable intermediary that regulates secretory production through the two-component system, providing a more reliable and understandable mechanism compared to simply reducing cell surface layer protein activity
3Quantity of substance
If multiple approaches are tried to improve secretory production (reducing cell surface layer protein activity, modifying penicillin-binding protein, etc.), then some improvement is achieved, but the process becomes complex
Solution Approach 1:
The patent extracts and focuses on a single key regulatory element (PhoS protein) within the two-component system to control secretory production. Instead of applying multiple complex genetic modifications to different targets, the patent isolates the PhoS mutation as the primary intervention point, simplifying the overall approach while achieving improved secretory production
Data Source
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AI summary
A novel technique for improving secretory production of a heterologous protein by coryneform bacteria is developed, and thereby a method for secretory production of a heterologous protein is provided. A coryneform bacterium having an ability of secretory production of a heterologous protein and has been modified so as to harbor a phoS gene having a specific mutation is cultured to produce the heterologous protein by secretory production.