Recombinant Heme Thiolate Oxygenases Through Derepressed Yeast Expression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for an effective expression system to produce unspecific peroxygenase enzymes (UPOs) in high yields and high enzyme activity, as recombinant expression in yeast species like Pichia pastoris has been challenging and largely unsolved, with previous methods yielding low enzyme levels and no successful secretion in Escherichia coli, Saccharomyces cerevisiae, or Pichia pastoris.
Innovation Solution
A method for producing recombinant polypeptides with peroxygenase activity in yeast cells using a derepressed promoter sequence, such as a methanol-independent CTA1 (PDC) or FMD promoter, and co-expression of helper proteins like PDI, which allows for high yields and secretion of polypeptides like heme thiolate peroxygenases in Pichia pastoris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional recombinant expression systems (E. coli, S. cerevisiae, P. pastoris with conventional promoters) are used to produce UPOs, then the expression can be established, but the enzyme yields are very low (less than 0.01 mg/L) and no active enzyme is produced
Solution Approach 1:
The patent changes the promoter parameter from conventional promoters (AOX1 requiring methanol, GAP requiring glucose repression) to a derepressed promoter that is constitutively active and not subject to carbon source repression. This parameter change enables continuous high-level expression without metabolic repression, resolving the contradiction between establishing expression and achieving high yields
Solution Approach 2:
The patent introduces an intermediary signaling pathway by using a promoter that responds to specific regulatory elements (likely involving transcription factors like Mot1p or other derepression mechanisms) rather than direct carbon source sensing. This intermediary mechanism allows decoupling of expression control from metabolic state, enabling reliable high-yield production independent of glucose repression
2Productivity
If methanol-inducible AOX1 promoter is used in P. pastoris, then expression can be achieved, but the promoter shows far less than 1% activity without methanol addition and requires complex induction protocols
Solution Approach 1:
The patent extracts the enzyme production function from the complex methanol induction system by using a promoter that is constitutively active without requiring methanol addition. This separates the expression function from the inducible system, eliminating the need for complex induction protocols while maintaining high productivity
Solution Approach 2:
Instead of using a repressible promoter that requires induction (AOX1), the patent inverts the approach by using a derepressed promoter that is naturally active and does not require induction. This inversion simplifies the operation from complex induction protocols to simple constitutive expression
3Productivity
If native signal sequences are used for secretion, then secretion can occur, but the secretion efficiency is limited and enzyme levels remain low (few mg/L)
Solution Approach 1:
The patent applies a universal secretion strategy by using strong signal sequences (like α-factor or CBH1) that are highly effective across different UPO enzymes and expression systems. These signal sequences provide universal high-efficiency secretion capability, replacing enzyme-specific native signals and enabling consistent high-level secretion regardless of the specific UPO being expressed
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 method achieves yields of up to 250 mg/L and titers of 300 mg/L of polypeptides with increased peroxygenase activity, surpassing previous expression systems, enabling their use in organic synthesis, polymerization, drug metabolite production, and environmental applications.
Implementation Method 1
a polynucleotide comprising a nucleic acid sequence encoding said polypeptide
Implementation Method 2
operably linked to a derepressed promoter sequence which is functional in methylotrophic yeasts
Implementation Method 3
oxygen-transferring enzymes can be used to solve this task through biocatalysis
Implementation Method 4
recombinant polypeptides having peroxygenase activity
Data Source
AI summary
The invention relates to polypeptides having peroxygenase activity and compositions comprising such polypeptides. The invention also relates to improved methods of producing such polypeptides in yeasts.