ADH Histidine Mutants for Cleaner Ni-NTA Protein Purification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing protein purification methods using Ni-NTA resin are hindered by non-target proteins with histidine residues binding to the resin, leading to impurities in the target protein preparation.
Innovation Solution
Engineering histidine residues of non-target proteins to reduce their affinity for Ni-NTA resin by mutating them to basic amino acids such as lysine, asparagine, or arginine, specifically in alcohol dehydrogenase (ADH) proteins at key positions, thereby enhancing the purity of target proteins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Ni-NTA resin is used for affinity chromatography purification, then target proteins with histidine tags can be purified, but non-target proteins with histidine residues also bind to the resin causing impurities
Solution Approach 1:
The patent applies parameter changes by mutating histidine residues to other amino acid residues (such as lysine, arginine, or alanine) at specific positions in non-target proteins. This changes the chemical properties of the protein surface, eliminating the coordination ability with nickel ions while maintaining the protein's native structure and function. The mutation strategy specifically targets histidine residues that are not involved in catalytic activity but are responsible for non-specific binding to Ni-NTA resin.
2Manufacturing precision
If histidine residues are mutated to eliminate binding to Ni medium, then purity of target protein improves, but enzymatic activity may be affected
Solution Approach 1:
The patent applies local quality by differentiating between different functional regions of the protein. Histidine residues are selectively mutated only in non-catalytic regions or regions not involved in substrate binding, while catalytic histidine residues are preserved. This localized approach ensures that the mutation eliminates non-specific binding without affecting the enzyme's catalytic function. The patent identifies specific positions for mutation based on structural and functional analysis.
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 ADH proteins exhibit reduced binding to Ni-NTA resin, improving the expression purity, efficiency, and yield of target proteins in cell-free synthesis systems while maintaining enzymatic activity.
Implementation Method 1
the corresponding imidazolyl group, thiol group or indolyl group can form coordination bond with metal ion
Implementation Method 2
The principle of immobilized metal-chelating affinity chromatography (IMAC) is mainly based on the fact that amino acid residues on protein surface can form different affinity with metal ions, which can be divided into three types: electrostatic attraction, covalent binding and coordination bond binding
Implementation Method 3
Affinity chromatography refers to a method that one of two molecules having affinity is fixed on an insoluble matrix, and the other molecule is separated and purified based on the specificity and reversibility of the affinity between the two molecules
Implementation Method 4
some non-target proteins also have several discontinuous histidine residues on the surface of their three-dimensional structure, which results in that those non-target proteins also bind to Ni-NTA resin
Data Source
AI summary
Provided are an ADH protein mutant and the use thereof. Compared with a wild-type ADH protein, the mutant is capable of (i) enhancing the expression purity, efficiency and yield of exogenous proteins in an in-vitro cell-free synthesis system; and/or (ii) reducing the binding ability of the mutant protein to Ni medium.