Multiprotein Complex Purification via Multi-Metal Chelate Precipitation
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Solution Overview
Problem
Current methods for metal affinity precipitation of proteins often result in low yields and purity, and are costly due to the use of solid supports and expensive reagents.
Innovation Solution
A method involving the expression of proteins of interest as fusion proteins with a multiprotein complex containing histidine-rich sequences, followed by assembly of the complex and treatment with a multi-metal chelate to form an affinity precipitate, which is then purified.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid supports are used for IMAC, then protein purification is achieved, but costs increase and cross-contamination occurs
Solution Approach 1:
The patent replaces expensive, reusable solid support materials with inexpensive, single-use precipitation reagents. The precipitation approach uses small molecule chelators that can be discarded after one use, eliminating the need for costly solid support cleanup and regeneration processes while preventing cross-contamination between batches.
Solution Approach 2:
The patent extracts the essential function of metal affinity binding from the solid support matrix and transfers it to soluble chelating reagents. By removing the solid support component entirely and using only the active chelating molecules in solution, the method achieves purification without the drawbacks of solid support-based IMAC.
2Ease of manufacture
If traditional precipitation methods are used, then cost is reduced, but yields and purity are low
Solution Approach 1:
The patent creates a composite system combining the low-cost advantage of precipitation reagents with the high-selectivity advantage of metal affinity binding. The soluble chelators form specific complexes with histidine-tagged proteins, providing both cost-effectiveness and high purification quality that neither approach achieves alone.
Solution Approach 2:
The patent changes the physical state parameter from solid support-bound reagents to soluble reagents, while optimizing chemical parameters such as chelator concentration, metal ion selection, and pH conditions to maximize both yield and purity. This parameter optimization enables precipitation methods to achieve previously unattainable purification quality.
3Productivity
If fast precipitation kinetics are achieved, then productivity increases, but selectivity may be compromised
Solution Approach 1:
The patent performs preliminary tagging of the target protein with a histidine-rich sequence before precipitation. This pre-modification ensures that only the tagged protein will bind to the metal-chelate reagents during the fast precipitation process, maintaining high selectivity even at rapid reaction speeds. The tag acts as a pre-installed recognition element that guides specific binding.
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 achieves high yields and purity of proteins with fast precipitation kinetics, reducing costs and preventing cross-contamination, while allowing for efficient purification and potential reuse of the protein catalyst.
Implementation Method 1
subjecting said MPC in solution to a multi-metal chelate in solution, thereby forming an affinity precipitate
Data Source
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AI summary
The present invention relates to a method for the purification of one or more recombinantly expressed protein(s) of interest (POI(s)), comprising the steps of expressing the POI(s) as a fusion protein in which one or more copies of the POI(s) is/are fused to a protomer of a multiprotein complex (MPC), assembling said MPC, said MPC comprising one or more of said fusion protein(s) and any further protomers that are part of said MPC, wherein one or more of the protomers assembled in the MPC contain(s) at least one histidine-rich amino acid sequence, subjecting said MPC in solution to a multi-metal chelate in solution, thereby forming an affinity precipitate, and purifying said affinity precipitate. The present invention further relates to respective affinity precipitates obtained by said method.