Periplasmic Polypeptide Isolation via Tris-EDTA Buffering
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Solution Overview
Problem
Current methods for isolating recombinantly produced polypeptides from the periplasm of prokaryotic cells, such as E. coli, are inefficient at large scales, leading to contamination with host cell proteins and difficulties in purification, particularly beyond small-scale cultures.
Innovation Solution
A method involving incubation of prokaryotic cells in a solution with a buffering agent like Tris and a chelating agent like EDTA at specific pH and temperature conditions, allowing for high-yield and high-purity isolation of polypeptides from the periplasm, facilitating downstream purification processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If osmotic shock method is used to isolate periplasmic polypeptides, then the outer membrane can be destabilized and polypeptides can be released, but the method is not practically accomplished at large scale (10 liters and above) and contamination with host cell proteins occurs
Solution Approach 1:
The patent applies parameter changes by optimizing pH (to alkaline conditions pH 8-10), temperature (room temperature or controlled conditions), and chemical composition (buffering agents like Tris, chelating agents like EDTA) of the isolation medium to achieve selective release of periplasmic polypeptides without contaminating host cell proteins, making the method scalable to large volumes
Solution Approach 2:
The patent uses buffering agents and chelating agents as intermediary substances that mediate the selective destabilization of the outer membrane and release of periplasmic contents. These intermediaries enable controlled isolation without direct mechanical disruption that would cause contamination
2Manufacturing precision
If conventional isolation methods are used, then small scale isolation can be achieved, but the method cannot be practically accomplished once cultures reach volumes at and above 10 liters
Solution Approach 1:
The patent creates a universal isolation method using a buffered system with chelating agents that functions effectively across all scale levels from small to large scale (10 liters and above). The method combines multiple functions: destabilizing outer membrane, releasing periplasmic contents, and maintaining polypeptide stability in a single scalable protocol
Solution Approach 2:
The patent optimizes parameters including pH (8-10), temperature, and chemical concentrations to ensure the isolation method maintains high purity while being scalable. The alkaline pH condition and chelating agent concentration are specifically tuned to work effectively at large scale without compromising purity
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
Enables efficient and pure isolation of recombinantly produced polypeptides at large scales, reducing contamination and improving the feasibility of subsequent purification steps, as demonstrated by successful isolation of proteins like α-Synuclein and Pseudomonas exotoxin.
Implementation Method 1
destabilizes the outer membrane of prokaryotic cells, which enables the penetration of sucrose into the periplasmic space
Implementation Method 2
water is soaked into the sucrose-filled periplasmic space and the destabilized outer membrane is disintegrated via the increase of the periplasmic volume
Implementation Method 3
Addition of MgCl2 re-stabilizes the outer membrane
Data Source
AI summary
Herein is reported a method for producing a polypeptide comprising the step of incubating (resuspended) prokaryotic cells in a solution comprising about 10 mM to about 95 mM Tris-HCl and about 2 mM to about 6 mM EDTA at a pH value of about 7 to about 10 for about 15 min to about 6 h at about 25° C.