Ig Binding Protein Composition for Alkali-Stable Antibody Purification
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Solution Overview
Problem
Existing Protein A-based chromatography matrices used for antibody purification lose binding capacity under harsh alkaline conditions and require thorough cleaning, limiting their reuse.
Innovation Solution
Development of Ig binding proteins with specific amino acid modifications, such as isoleucine or leucine at position 8, providing stability under alkaline conditions for at least 20 hours and maintaining high binding capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Protein A-based chromatography matrices are used for antibody purification, then high binding capacity is achieved, but binding capacity is lost under harsh alkaline conditions
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid composition of Protein A, specifically replacing certain amino acids with others that have different chemical properties (e.g., replacing Asp8 with Lys8, Arg31 with Lys31, Asp38 with Lys38) to enhance resistance to alkaline conditions while preserving binding capacity
Solution Approach 2:
The patent creates composite materials by combining modified Protein A variants with chromatography matrix support materials, resulting in affinity matrices that exhibit both high binding capacity and improved stability under harsh cleaning conditions
2Productivity
If Protein A-based chromatography matrices are reused multiple times, then productivity increases, but cleaning under harsh conditions causes loss of binding capacity
Solution Approach 1:
The patent applies preliminary action by pre-modifying the Protein A structure with amino acid substitutions before the chromatography process begins, enabling the matrix to withstand harsh cleaning procedures and maintain binding capacity across multiple reuse cycles
3Ease of operation
If harsh alkaline cleaning solutions are applied to affinity ligand matrices, then contaminants are removed, but Protein A domains lose binding capacity
Solution Approach 1:
The patent modifies the chemical parameters of Protein A through amino acid substitution, changing its resistance properties to alkaline environments, allowing it to withstand harsh cleaning solutions without losing binding capacity
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 Ig binding proteins maintain high binding capacity and stability under alkaline conditions, enabling multiple uses of the affinity matrices without significant loss of performance.
Implementation Method 1
immunoglobulin (Ig) binding proteins comprising one or more domains having highly hydrophobic amino acids with branched side chains (Iso, Leu, Val), or aromatic amino acids (Tyr, Phe, or Trp), corresponding to positions 4 or 6 or 8 of the Ig binding protein
Implementation Method 2
An established procedure for capturing and purifying antibodies is affinity chromatography using the bacterial cell surface Protein A from Staphylococcus aureus as selective ligand for immunoglobulins
Data Source
AI summary
The present invention relates to immunoglobulin (Ig) binding proteins comprising one or more domains having highly hydrophobic amino acids with branched side chains (Iso, Leu, Val), or aromatic amino acids (Tyr, Phe, or Trp) corresponding to position 4 or 6 or 8 of the Ig binding protein of SEQ ID NO: 1 or functionally similar proteins. The novel proteins have superior properties for highly efficient purification methods for antibodies (immunoglobulins), for example, the proteins have high binding capacity and high chemical stability. The invention further relates to affinity matrices comprising the Ig binding proteins of the invention. The invention also relates to a use of these Ig binding proteins or affinity matrices for affinity purification of immunoglobulins and to methods of affinity purification using the Ig binding proteins of the invention.