Recombinant Protein Production Using Membrane-Permeable Reducing Agents
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Solution Overview
Problem
Current methods for producing recombinant proteins in bacterial cells, such as E. coli, face challenges with protein aggregation and improper folding due to the host's inability to handle proteins with unusual features like disulfide bonds or high hydrophobicity, leading to low yields and insolubility, especially for proteins with reduced cysteines like ribonuclease inhibitors.
Innovation Solution
Incorporating a membrane-permeable reducing agent, like dithiothreitol (DTT), into the culture media to maintain cysteine residues in a reduced state, facilitating the production of proteins with disulfide bonds or without them, thereby enhancing soluble accumulation and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If recombinant proteins are produced in bacterial cells using conventional methods, then production speed and simplicity are maintained, but protein aggregation and improper folding occur leading to low yields
Solution Approach 1:
The patent changes the chemical parameters of the cultivation medium by adding reducing agents (DTT, beta-mercaptoethanol, cysteine) to alter the redox environment. This parameter change prevents disulfide bond formation and maintains cysteine residues in reduced state, thereby preventing protein aggregation and improving soluble protein yield while maintaining production efficiency
2Reliability
If proteins with disulfide bonds are produced in bacterial periplasmic space, then disulfide bond formation is facilitated, but protein solubility and proper folding are compromised
Solution Approach 1:
Instead of relying on the natural oxidative environment of the periplasmic space for disulfide bond formation, the patent inverts the approach by adding reducing agents to the cultivation medium. This creates a reducing environment that prevents unwanted disulfide bonds and aggregation, while still allowing proper folding through alternative mechanisms
3Stability of the object's composition
If reducing agents are added to cultivation medium, then cysteine residues remain in reduced state improving protein solubility, but disulfide bond formation is inhibited
Solution Approach 1:
The patent systematically adjusts the redox parameters of the cultivation medium by controlling reducing agent concentration, pH, and temperature. These parameter changes create optimal conditions for maintaining reduced cysteine residues while preventing aggregation, effectively decoupling solubility maintenance from disulfide bond formation requirements
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 use of DTT in the culture media significantly improves the production and solubility of recombinant proteins by maintaining cysteine residues in a reduced state, leading to higher yields and activity of proteins like ribonuclease inhibitors, even in bacterial cells.
Implementation Method 1
wherein said reducing agent is capable of permeating the plasma membrane of the host cells
Implementation Method 2
the use of DTT in the culture media significantly improves the production and solubility of recombinant proteins by maintaining cysteine residues in a reduced state
Data Source
AI summary
A method for producing from host cells a heterologous polypeptide or protein comprising at least one cysteine residue in a reduced state. The method cultured the host cells in a culture medium comprising a reducing agent; and recovered the heterologous polypeptide or protein comprising at least one cysteine residue in a reduced state from the host cells or from the culture medium, where the host cells comprise a nucleic acid encoding the heterologous protein or polypeptide, and where the reducing agent is capable of permeating the plasma membrane of the host cells.