Mutant Protein L Antibody Purification Mild Acid Dissociation
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Solution Overview
Problem
Conventional affinity supports have insufficient purification efficiency for antibodies under mild acidic conditions, and there is a need for an immunoglobulin binding protein with enhanced antibody dissociation rates under these conditions.
Innovation Solution
A mutant immunoglobulin binding protein derived from protein L, with specific amino acid sequence mutations, is used as an affinity ligand, providing high binding activity and efficient antibody dissociation under mild acidic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional affinity supports are used for antibody purification, then the binding capacity is maintained, but the purification efficiency under mild acidic conditions is insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of protein L at specific positions (16, 18, 20, 26, 28, 30, 32, 34, 35, 38, 42, 54, 57, 70) to alter the dissociation behavior of antibodies under acidic conditions. These sequence modifications change the chemical properties of the binding interface, enabling enhanced dissociation rates at mild acidic pH while preserving binding capacity.
Solution Approach 2:
The invention applies local quality by making site-specific mutations at particular amino acid positions within the protein L sequence rather than uniform modifications throughout the entire protein. This targeted approach allows optimization of dissociation behavior at the binding interface while maintaining the overall structural integrity and binding capacity of the protein.
2Reliability
If strongly acidic conditions are used for elution, then the dissociation of antibody from ligand is improved, but the antibody may be damaged by denaturation
Solution Approach 1:
The mutated protein L exhibits parameter changes in its dissociation behavior, achieving high dissociation rates at mild acidic conditions (pH 3.0-4.5) compared to conventional protein L that requires strongly acidic conditions. This shift in dissociation pH profile allows elution without exposing antibodies to denaturing strongly acidic environments.
Solution Approach 2:
The invention converts the normally harmful effect of acidic conditions into a beneficial feature by engineering the protein L mutant to have enhanced dissociation at mild acidic pH. What would normally be a compromise between dissociation efficiency and antibody stability becomes an advantage, where mild acidity simultaneously achieves both effective dissociation and antibody protection.
3Object-affected harmful factors
If mild acidic conditions are used for elution, then the antibody damage is reduced, but the purification efficiency is lowered due to difficult dissociation
Solution Approach 1:
The amino acid sequence modifications in protein L mutant fundamentally change the pH-dependent dissociation profile, transforming mild acidic conditions from a state of poor dissociation into one of optimal dissociation. This parameter change enables simultaneous achievement of high purification efficiency and antibody protection under the same mild acidic conditions.
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 mutant immunoglobulin binding protein exhibits enhanced antibody dissociation rates and binding activity, improving the efficiency of antibody purification under mild acidic conditions, reducing the risk of antibody denaturation.
Implementation Method 1
the mutant has immunoglobulin κ chain binding activity
Data Source
AI summary
Provided are a protein L-derived immunoglobulin binding protein having an increased antibody dissociation rate under acidic conditions, and an affinity support using the same. Disclosed are an immunoglobulin binding protein comprising at least one mutant of an immunoglobulin binding domain, and an affinity support comprising a solid-phase support having the immunoglobulin binding protein bound thereto. A mutant of the immunoglobulin binding domain consists of an amino acid sequence having an identity of at least 85% with the sequence set forth in any one of SEQ ID NO:1 to SEQ ID NO:9 and a predetermined mutation, and the mutant has immunoglobulin κ chain binding activity.