Alkali-Stabilized Protein A Chromatography Matrix Cleaning
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Solution Overview
Problem
Current affinity chromatography matrices with protein A ligands face challenges in withstanding high alkaline pH conditions during cleaning and sanitization, leading to reduced capacity and inefficiency in immunoglobulin purification, particularly due to the sensitivity of existing mutants to NaOH concentrations.
Innovation Solution
Development of multimers of immunoglobulin-binding alkali-stabilized Protein A domains with specific mutations, such as at positions 3, 13, and 44, which are covalently coupled to a porous support, allowing for the use of concentrated aqueous alkali metal hydroxide solutions for cleaning and sanitization, enhancing stability and binding capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protein A ligands are used in affinity chromatography matrices, then immunoglobulin purification can be performed, but the matrices suffer from reduced capacity and instability when exposed to high alkaline pH conditions during cleaning and sanitization
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of Protein A ligands through site-directed mutagenesis. Specific mutations (e.g., N11E, N11K, Q9A, Q9E) are introduced to alter the chemical properties of the ligand, making it resistant to alkaline pH conditions. This allows the matrix to withstand high concentration NaOH cleaning solutions (up to 1M or higher) without significant capacity loss, resolving the contradiction between purification effectiveness and cleaning durability.
Solution Approach 2:
The patent creates composite materials by combining mutated Protein A domains with porous support matrices. The mutated Protein A ligands are covalently coupled to the support, forming a composite structure that integrates the stability benefits of the engineered protein with the functional properties of the porous matrix. This composite approach enables simultaneous achievement of high alkali stability and effective immunoglobulin binding.
2Ease of operation
If high concentration NaOH solutions are used for cleaning and sanitization, then effective removal of contaminants and inactivation of microorganisms is achieved, but existing protein A matrices experience capacity loss due to ligand instability
Solution Approach 1:
The patent uses parameter changes by systematically mutating specific amino acid positions in Protein A (particularly positions 9, 11, and others) to enhance alkaline stability. These mutations allow the ligand to maintain its binding capacity even when exposed to high concentration NaOH cleaning solutions, enabling effective cleaning without significant capacity loss. The modified ligands can withstand repeated cleaning cycles with 1M or higher NaOH concentrations.
Solution Approach 2:
The patent effectively extends the operational life of the affinity matrix by making it resistant to harsh cleaning conditions. Instead of requiring frequent replacement or gentle cleaning that compromises contamination removal, the engineered matrices can undergo intensive cleaning with high concentration NaOH and alcohol solutions without degradation, significantly reducing replacement frequency and operational costs.
3Reliability
If alcohol-based sanitizers are used to avoid alkaline damage, then matrix stability is maintained, but sanitization effectiveness is reduced and capacity loss still occurs
Solution Approach 1:
The patent applies parameter changes by engineering Protein A ligands with enhanced alkaline resistance through specific amino acid mutations. This enables the use of high concentration NaOH solutions for both cleaning and sanitization purposes, eliminating the need to compromise between stability and sanitization effectiveness. The mutated ligands withstand the harsh conditions while maintaining binding capacity.
Solution Approach 2:
The patent achieves multi-functionality by designing Protein A variants that can simultaneously withstand intensive cleaning with high concentration NaOH and effective sanitization protocols. The engineered ligands serve multiple functions: maintaining stability during harsh cleaning, allowing effective microorganism inactivation, and preserving binding capacity for subsequent purification cycles, replacing the need for separate gentle cleaning and alcohol sanitization steps.
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 method enables effective cleaning and sanitization of affinity separation matrices with retained dynamic binding capacity, allowing for the purification of various immunoglobulin products without significant capacity loss, and reduces the need for alcohol-based sanitizers.
Implementation Method 1
cleaning the matrix of contaminants usually involves a procedure known as cleaning-in-place (CIP), wherein agents capable of eluting contaminants from the stationary phase are used. Inactivation of microorganisms usually involves a procedure known as sanitization-in-place (SIP) wherein agents capable of inactivating microorganisms are used. Some agents are capable of both cleaning and sanitizing the separation matrix, depending on the concentration of the agent and the contact time with the separation matrix. One such class of agents often used is alkaline solutions that are passed over said stationary phase.
Implementation Method 2
At present the most extensively used cleaning and sanitizing agent for most separation matrices is NaOH, and the concentration thereof can range from 0.1 up to e.g. 1 M, depending on the degree and nature of contamination.
Implementation Method 3
Affinity chromatography is used in most cases, as one of the key steps in the purification of these immunoglobulin molecules. A particularly interesting class of affinity reagents is proteins capable of specific binding to invariable parts of an immunoglobulin molecule, such interaction being independent on the antigen-binding specificity of the antibody. An example of such a protein is staphylococcal protein A, containing domains capable of binding to the Fc and Fab portions of IgG immunoglobulins from different species.
Implementation Method 4
Staphylococcal protein A (SpA) based reagents have due to their high affinity and selectivity found a widespread use in the field of biotechnology, e.g. in affinity chromatography for capture and purification of antibodies
Data Source
AI summary
The present invention concerns a method of cleaning and/or sanitizing a separation matrix comprising multimers of immunoglobulin-binding alkali-stabilized Protein A domains covalently coupled to a porous support. The method comprises the steps of:a) optionally purifying a mixture comprising a first immunoglobulin using the separation matrix;b) providing a cleaning liquid comprising at least 50% by volume of an aqueous alkali metal hydroxide solution; andc) cleaning and/or sanitizing the separation matrix by contacting the cleaning liquid with the separation matrix for a predetermined contact time.The alkali-stabilized Protein A domains comprise mutants of a parental Fc-binding domain of Staphylococcus Protein A (SpA), as defined by SEQ ID NO 51 or SEQ ID NO 52, wherein the amino acid residues at positions 13 and 44 of SEQ ID NO 51 or 52 are asparagines and wherein at least the asparagine residue at position 3 of SEQ ID NO 51 or 52 has been mutated to an amino acid selected from the group consisting of glutamic acid, lysine, tyrosine, threonine, phenylalanine, leucine, isoleucine, tryptophan, methionine, valine, alanine, histidine and arginine.