Mutated Protein A Ligands Alkaline Stability
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Solution Overview
Problem
Current affinity chromatography matrices containing protein A ligands are sensitive to alkaline pH conditions during cleaning-in-place procedures, limiting the effectiveness of cleaning and leading to capacity losses, as they are not stable enough to withstand higher NaOH concentrations.
Innovation Solution
Development of mutated polypeptides and multimers of Staphylococcal Protein A with specific mutations, such as replacing the glutamine residue at position 9 with other amino acids, which enhance alkaline stability without compromising immunoglobulin-binding properties, allowing for improved resistance to alkaline cleaning solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If higher NaOH concentrations are used for cleaning, then cleaning effectiveness is improved, but protein A ligand stability deteriorates
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., N3D, N6D, N21D, N28D, N33D, Q9A) are introduced to alter the chemical stability parameters of the ligand, enabling it to withstand higher NaOH concentrations (up to 2.0 M) during cleaning-in-place procedures without significant capacity loss, thereby resolving the contradiction between cleaning effectiveness and ligand stability
Solution Approach 2:
The patent creates composite materials by combining mutated protein A domains with support matrices. The engineered protein A variants are immobilized on chromatography supports to form composite affinity media that exhibit both high cleaning stability (resistance to 2.0 M NaOH) and maintained immunoglobulin binding capacity, effectively combining the properties of chemical stability and biological functionality
2Productivity
If repeated cleaning cycles are performed, then matrix regeneration is improved, but binding capacity deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-engineering the protein A ligands with stabilizing mutations before they are exposed to cleaning cycles. The mutations (particularly in the B domain residues) are introduced in advance to prevent alkaline-induced degradation, allowing the matrix to undergo repeated regeneration cycles with minimal capacity loss. This preliminary structural reinforcement enables the matrix to maintain 80% or more of its initial binding capacity after multiple cleaning cycles
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 polypeptides and multimers provide enhanced alkaline stability, enabling more effective cleaning of affinity chromatography matrices, maintaining binding capacity and immunoglobulin-binding properties even after repeated exposure to alkaline conditions, thus improving the efficiency and longevity of the separation process.
Implementation Method 1
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 2
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 discloses a polypeptide with improved alkaline stability, which polypeptide comprises a mutant of a B or C domain of Staphylococcus Protein A (SpA), as specified by SEQ ID NO 1 or SEQ ID NO 2, or of Protein Z, as specified by SEQ ID NO 3, wherein at least the glutamine residue at position 9 has been mutated to an amino acid other than asparagine. The invention also discloses multimers of said polypeptide, as well as separation matrices comprising the multimers or polypeptides.