Purifying Recombinant Plasmodium falciparum Circumsporozoite Protein
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Solution Overview
Problem
Current methods for purifying recombinant Plasmodium falciparum circumsporozoite protein (rCSP) face challenges such as dimerization, aggregation, and N-terminal degradation, leading to low yields and inefficiencies in scalable production, particularly due to the formation of covalent intermolecular disulfide bonds and the need for denaturing and refolding processes.
Innovation Solution
A process involving the separation of bacterial cell lysate into soluble and insoluble fractions, followed by preferential reducing conditions using mild reducing agents and disaggregating agents to reduce intermolecular disulfide bonds while preserving intramolecular bonds, allowing for the purification of rCSP without denaturation and refolding, thereby maintaining the N-terminus integrity and achieving high yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional purification schemes are used to obtain recombinant CSP, then the protein can be purified, but the N-terminal region is highly susceptible to degradation and yields are low
Solution Approach 1:
The patent changes the pH parameter during purification to maintain the N-terminal region integrity. By controlling pH conditions throughout the purification process, the method prevents N-terminal degradation while achieving high yields of intact CSP protein
Solution Approach 2:
The patent performs preliminary protease inhibition before purification begins. By adding protease inhibitors at the start of the process and maintaining them throughout, the N-terminal region is protected from degradation before it can be damaged, enabling high recovery of intact protein
2Manufacturing precision
If denaturing and refolding steps are used to eliminate dimers and aggregates, then protein purity is improved, but the process becomes complicated and costly with reduced yield
Solution Approach 1:
The patent extracts and removes dimers and aggregates through size-exclusion chromatography without requiring denaturation. By using a gentle separation method that exploits size differences, the process eliminates the need for harsh denaturing and refolding steps, simplifying the workflow while maintaining purity
Solution Approach 2:
The patent uses size-exclusion chromatography as an intermediary separation method. This technique acts as a mediator that separates monomers from dimers and aggregates based on hydrodynamic radius without disrupting protein structure, avoiding the need for denaturation while achieving high purity
3Manufacturing precision
If denaturing and refolding steps are used to eliminate dimers and aggregates, then protein purity is improved, but yield is reduced and scaling up becomes challenging
Solution Approach 1:
The patent extracts and removes dimers and aggregates through size-exclusion chromatography without requiring denaturation. By using a gentle separation method that exploits size differences, the process eliminates the need for harsh denaturation and refolding steps, simplifying the workflow while maintaining purity
Solution Approach 2:
The patent maintains continuous protection of the N-terminal region throughout the entire purification process by keeping protease inhibitors present from start to finish. This continuous protective action prevents degradation at all stages, ensuring high yield of intact protein without interruption or loss
4Manufacturing precision
If denaturing and refolding steps are used to eliminate dimers and aggregates, then protein purity is improved, but the process becomes costly
Solution Approach 1:
The patent extracts and removes dimers and aggregates through size-exclusion chromatography without requiring denaturation. By using a gentle separation method that exploits size differences, the process eliminates the need for harsh denaturation and refolding steps, simplifying the workflow while maintaining purity
Solution Approach 2:
The patent uses disposable protease inhibitor cocktails that can be added directly to the purification buffer. These inexpensive, ready-to-use inhibitors provide continuous protection without requiring complex recovery or regeneration, reducing overall manufacturing costs while maintaining protein integrity
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 effectively purifies rCSP with high yields, maintaining N-terminus integrity and reducing the formation of dimers and aggregates, thus improving the quality and quantity of the purified protein, making it suitable for large-scale production.
Implementation Method 1
subjecting the recombinant P. falciparum circumsporozoite protein dimers to preferential reducing conditions, wherein the preferential reducing conditions comprise a mild reducing agent selected from DTT, cysteine, acetylcysteine, glutathione, monothioglycerol (MTG), thioglycolate, dithiothreitol, dithioerythritol, 2-Mercaptoethanol (β-mercaptoethanol), TCEP-HCl (pure, crystalline Tris(2-carboxyethyl)phosphine hydrochloride), and 2-Mercaptoethylamine-HCl (2-MEA)
Implementation Method 2
The purified recombinant P. falciparum circumsporozoite protein obtained is N-terminally intact from residue 25 of SEQ ID NO: 1, and wherein not more than 10% of the purified recombinant P. falciparum circumsporozoite protein obtained is dimerized, and not more than 5% of the purified recombinant P. falciparum circumsporozoite protein obtained is present as high molecular weight aggregates
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
The present invention relates to processes for purifying high-quality recombinant Plasmodium falciparum circumsporozoite protein at high yields. This process provides rCSP at high yields without the need for denaturing and refolding the protein. The present invention overcomes obstacles previously encountered in the field, including dimerization, aggregation, and N-terminal degradation of rCSP. The process provided by the invention is scalable, and can be applied to large fermentation batches. The invention also relates to stable liquid formulations of recombinant P. falciparum circumsporozoite protein, and processes for stably maintaining rCSP in a stable liquid formulation.