Mutated Protein A for Alkaline Tolerance in Antibody Purification
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Solution Overview
Problem
Current immunoglobulin-binding proteins, such as Protein A, face limitations in alkali tolerance during the purification of monoclonal antibodies, as they are vulnerable to alkaline conditions, which affects their stability and efficiency in affinity chromatography.
Innovation Solution
A mutated immunoglobulin-binding protein is developed by randomly substituting amino acids at specific positions (18th, 36th, 43rd, and 52nd) in the domain A of Protein A, enhancing its alkali tolerance through genetic engineering and protein engineering methods, maintaining affinity to immunoglobulins while improving chemical stability under alkaline conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If NaOH is used for cleaning-in-place to remove contaminants, then cleaning efficiency is improved, but protein-based refining resins are damaged due to alkali vulnerability
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid composition of Protein A to increase resistance to alkaline conditions. Specifically, the patent develops mutated Protein A variants with altered amino acid sequences that maintain structural stability and binding affinity under high pH conditions, enabling the resin to withstand NaOH cleaning without degradation
Solution Approach 2:
The patent creates a composite material by combining Protein A with specific amino acid mutations that confer alkali resistance. The mutated Protein A forms a composite structure that integrates the natural antibody-binding properties of Protein A with enhanced chemical stability, allowing it to function as both a purification medium and a cleaning-resistant material
2Reliability
If Protein A is washed with NaOH to maintain stability, then alkali resistance is improved, but cleaning efficiency is limited compared to stronger alkaline treatments
Solution Approach 1:
The patent modifies the chemical parameters of Protein A by introducing specific amino acid mutations that increase pI (isoelectric point) and alter side chain composition. These parameter changes enable the protein to maintain stability at higher pH levels, allowing more aggressive alkaline cleaning protocols to be used without compromising resin integrity
3Temperature
If Asn residues are replaced to increase thermal stability, then thermal stability is improved, but alkali tolerance is reduced
Solution Approach 1:
The patent applies local quality by making site-specific amino acid replacements at particular positions within the Protein A structure. Instead of global modifications, the patent targets specific residues (such as positions 30, 36, 43, and 52 in Domain A) with mutations that locally enhance alkali resistance while preserving overall protein fold and function
Solution Approach 2:
The patent changes specific local parameters of the Protein A structure by replacing Asn residues with amino acids that have different side chain properties (such as Ala, Ser, Thr, or other non-Asn residues). These localized parameter changes reduce susceptibility to alkaline hydrolysis at critical positions without disrupting the global structural parameters that confer thermal stability
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 mutated protein exhibits significantly increased alkali tolerance and stability, allowing for more efficient antibody purification and resistance to alkaline washing, surpassing the stability of commercial resins like MabSelect Sure.
Implementation Method 1
Affinity chromatography using protein A, which is an antibody affinity ligand capable of selectively recovering monoclonal antibodies from a medium
Implementation Method 2
the mutated protein exhibits significantly increased alkali tolerance and stability, allowing for more efficient antibody purification and resistance to alkaline washing
Data Source
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AI summary
The present invention relates to a mutated immunoglobulin-binding protein having increased alkaline tolerance and, more specifically, to an immunoglobulin-binding protein in which, with respect to the A-domain of Staphylococcal protein A, or a functional variant thereof, an amino acid at a specific site is mutated and thereby exhibits an increased chemical stability at an alkaline pH value in comparison to a parental molecule. The present invention can provide an antibody-purifying immunoglobulin-binding protein ligand and matrix which have enhanced alkaline tolerance and accordingly enhanced stability in multiple times of alkaline cleaning.