Alkali-Stable Protein A Chromatography Matrix
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Solution Overview
Problem
Current affinity chromatography matrices with protein A ligands face challenges in alkaline stability, limiting the effectiveness of cleaning procedures and reducing the capacity for immunoglobulin purification, as they are sensitive to high pH conditions during cleaning-in-place processes.
Innovation Solution
A mutant Fc-binding polypeptide of Staphylococcus Protein A with specific mutations, such as replacing asparagine at position 11 with amino acids like glutamic acid or lysine, and multimers thereof, are used to create a separation matrix with enhanced alkaline stability, allowing for improved binding capacity and resistance to alkaline cleaning agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If native or recombinant protein A ligands are used in affinity chromatography matrices, then high affinity and selectivity for immunoglobulins are achieved, but the matrices exhibit decreased stability and capacity under alkaline cleaning conditions
Solution Approach 1:
The patent applies parameter changes by mutating specific amino acid residues in the protein A sequence (particularly asparagine residues at positions 11, 23, and 43) to alter the chemical stability parameters of the ligand. These mutations change the protein's resistance to alkaline conditions without significantly affecting its immunoglobulin binding capability, thereby resolving the contradiction between alkaline stability and purification capacity.
Solution Approach 2:
The invention creates composite affinity ligands by combining mutated protein A domains with support matrices. The mutated protein A domains serve as functional components with enhanced alkaline stability, while the support matrix provides structural framework. This composite structure maintains high purification capacity while improving resistance to alkaline cleaning agents.
2Ease of manufacture
If high concentrations of NaOH are used for cleaning-in-place procedures, then effective removal of contaminants is achieved, but the protein A ligand capacity decreases due to instability at high pH
Solution Approach 1:
The patent changes the chemical parameters of the protein A ligand through site-directed mutagenesis, specifically replacing pH-sensitive asparagine residues with more alkaline-stable amino acids. This parameter change allows the ligand to withstand high pH cleaning conditions (up to pH 13-14) without significant capacity loss, enabling effective cleaning-in-place procedures.
Solution Approach 2:
The invention performs preliminary chemical modification of the protein A ligand before it is exposed to harsh cleaning conditions. By pre-mutating the amino acid sequences to be more alkaline-resistant, the ligand is prepared in advance to withstand the high pH cleaning processes without degradation, thus maintaining both cleaning effectiveness and ligand stability.
3Ease of repair
If protein A ligands are exposed to repeated alkaline cleaning cycles, then matrix regeneration is achieved, but capacity loss occurs due to ligand instability
Solution Approach 1:
The patent implements parameter changes in the protein A sequence to enhance its durability under repeated alkaline exposure. The mutations in asparagine residues create a ligand variant that maintains its binding capacity through multiple cleaning cycles, directly addressing the capacity retention issue while enabling matrix regeneration.
Solution Approach 2:
The invention applies a more extreme approach than conventional protein A by introducing multiple mutations at key positions (N11, N23, N43) to achieve excessive alkaline stability. This partial or excessive modification ensures that the ligand can withstand more rigorous and repeated cleaning cycles than standard protein A, maintaining capacity retention while enabling thorough matrix regeneration.
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 modified separation matrix maintains high selective binding to immunoglobulins and exhibits increased stability and capacity under alkaline conditions, enabling more efficient and economical purification of immunoglobulins by withstanding harsh cleaning processes.
Implementation Method 1
affinity chromatography is used in most cases, as one of the key steps in the purification of these immunoglobulin molecules
Implementation Method 2
proteins capable of specific binding to invariable parts of an immunoglobulin molecule, such interaction being independent on the antigen-binding specificity of the antibody
Implementation Method 3
Such removal usually involves a procedure known as cleaning-in-place (CIP), wherein agents capable of eluting contaminants from the stationary phase are used. One such class of agents often used is alkaline solutions that are passed over said stationary phase
Data Source
AI summary
The invention relates to a method of isolating an immunoglobulin, comprising the steps of:a) providing a separation matrix comprising at least 15 mg/ml multimers of immunoglobulin-binding alkali-stabilized Protein A domains covalently coupled to a porous support, wherein the porous support comprises cross-linked polymer particles having a volume-weighted median diameter (d50,v) of 56-70 micrometers and a dry solids weight of 55-80 mg/ml;b) contacting a liquid sample comprising an immunoglobulin with the separation matrix;c) washing the separation matrix with a washing liquid;d) eluting the immunoglobulin from the separation matrix with an elution liquid; ande) cleaning the separation matrix with a cleaning liquid comprising at least 0.5 M NaOH.