Recombinant IL-11 Yeast Expression and Purification
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Solution Overview
Problem
The production of recombinant IL-11 at adequate scale and purity is challenging due to issues like insoluble inclusion bodies in bacteria, low yields in yeast, and complex culture requirements in mammalian and insect cells, leading to product heterogeneity and purification complications.
Innovation Solution
A method involving the expression of recombinant IL-11 in yeast without fusion proteins, using polyethylene glycol for precipitation, denaturants for solubilization and refolding, and chromatographic steps like ion exchange and hydrophobic interaction chromatography to achieve high purity and reduced dimer and oxidation content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If recombinant IL-11 is expressed in bacteria, then production scale can be achieved, but the protein forms insoluble inclusion bodies resulting in poor yields
Solution Approach 1:
The patent uses a fusion protein strategy where IL-11 is expressed as a fusion with a soluble partner protein in bacteria. This intermediary fusion construct acts as a mediator that enables proper folding and solubility of IL-11 during expression, preventing inclusion body formation while maintaining high-yield bacterial production capabilities
Solution Approach 2:
The patent modifies expression parameters including using optimized promoters, adjusting induction conditions, and controlling growth temperature to improve protein solubility and folding efficiency while maintaining high-level expression in bacterial systems
2Manufacturing precision
If recombinant IL-11 is expressed in yeast, then proper folding can be achieved, but yields remain low
Solution Approach 1:
The patent creates multiple copies of the IL-11 gene integrated into the yeast genome rather than using a single plasmid copy, thereby copying the expression capability across multiple genomic locations to achieve both proper folding and high-yield production in yeast systems
Solution Approach 2:
The patent optimizes yeast expression parameters including strain selection, induction timing, and culture conditions to maximize IL-11 yield while maintaining the eukaryotic folding advantages of the yeast system
3Productivity
If fusion proteins are used to improve expression characteristics, then production yield increases, but product heterogeneity occurs due to cleavage variations
Solution Approach 1:
The patent extracts and removes the fusion partner sequence through site-specific cleavage using engineered protease recognition sites, separating the IL-11 product from the fusion construct. This extraction approach enables recovery of homogeneous IL-11 while maintaining the production advantages of fusion protein expression
Solution Approach 2:
The patent introduces site-specific protease recognition sequences as intermediary elements within the fusion protein that enable precise and homogeneous cleavage. These engineered cleavage sites act as mediators that facilitate clean separation of IL-11 from the fusion partner, reducing product heterogeneity
4Manufacturing precision
If complex culture systems like mammalian or insect cells are used, then proper protein folding can be achieved, but culture requirements become complex complicating purification
Solution Approach 1:
The patent employs yeast, a simpler eukaryotic system that provides essential folding capabilities while being easier to culture and process than mammalian or insect cells. The yeast system serves itself to provide proper disulfide bond formation and folding without requiring the complex infrastructure of higher eukaryotic cell systems
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
This method results in a highly purified, active, and monomeric recombinant IL-11 with a purity of at least 95% and biological activity of 4×10^6 U/mg to 1.2×10^7 U/mg, effectively addressing the challenges of yield and heterogeneity in previous methods.
Implementation Method 1
The supernatant is treated with polyethylene glycol in quantities sufficient to form a suspension that includes a precipitate
Implementation Method 2
The precipitate is solubilized in a solution that includes a denaturant, producing a crude IL-11 solution
Implementation Method 3
The refolded IL-11 solution is then brought into contact with an ion exchange media, and a purified IL-11 is subsequently eluted from the ion exchange media
Implementation Method 4
The purified IL-11 is brought into contact with a hydrophobic interaction media. A polished IL-11, which has a reduced content of oxidized IL-11 relative to the purified IL-11, is subsequently eluted from the hydrophobic interaction media
Data Source
AI summary
Recombinant interleukin-11 (rhIL-11) is expressed in yeast, then isolated from aerobic fermentation media by precipitation, solubilization of the precipitate in the presence of a denaturant, and renaturation of the solubilized protein. Renatured rhIL-11 is further purified by cation exchange and hydrophobic interaction chromatography to provide a highly purified rhIL-11 with high biological activity and low rhIL-11 dimer and oxidized rhIL-11 content.