Alpha-Amylase Variants for Low-pH and Low-Calcium Stability
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Solution Overview
Problem
Current alpha-amylases face stability issues at low sodium ion concentrations, low pH, and high temperatures, particularly at low calcium concentrations, which affects their performance in starch processing and other industrial applications.
Innovation Solution
Development of alpha-amylase variants with specific substitutions, such as K176L+E185P+I201Y+H205Y+K213T+Q360S+D416V+R437W, and additional lysine residue substitutions, which enhance stability and activity on long chain substrates, improving performance in challenging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If alpha-amylases are used in industrial processes, then starch processing and other applications are enabled, but stability deteriorates at low sodium ion concentrations, low pH, and high temperatures
Solution Approach 1:
The patent applies parameter changes by modifying amino acid residues at specific positions (K176, E185, I201, H205, K213, Q360, D416, R437) in the alpha-amylase protein structure. These substitutions alter the physical and chemical parameters of the enzyme, enhancing its stability under extreme conditions (low pH, high temperature, low sodium and calcium concentrations) while maintaining its catalytic activity for starch processing
Solution Approach 2:
The patent applies local quality by making targeted amino acid substitutions at specific local positions (K176L, E185P, I201Y, H205Y, K213T, Q360S, D416V, R437W) rather than uniform modifications throughout the protein. This localized modification approach allows the enzyme to maintain its overall structure and function while improving stability at critical regions that interact with ions and withstand environmental stress
2Adaptability or versatility
If alpha-amylases are used at low calcium concentrations, then process flexibility is improved, but stability deteriorates
Solution Approach 1:
The patent modifies the enzyme's parameter sensitivity by substituting amino acids at positions that interact with calcium ions and maintain structural integrity. The variants (K176L+E185P+I201Y+H205Y+K213T+Q360S+D416V+R437W) reduce dependence on calcium concentration, allowing the enzyme to maintain stability across a broader range of calcium levels and enabling greater process flexibility
3Reliability
If protein engineered variants are developed to improve stability, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent maintains simplicity by applying local quality - making only 8 specific amino acid substitutions at predetermined positions (K176, E185, I201, H205, K213, Q360, D416, R437) rather than comprehensive protein engineering. This targeted approach improves stability while keeping the overall protein structure and sequence relatively simple and easy to produce industrially
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 variants demonstrate improved stability in the presence of glucose and increased activity on long chain substrates compared to mature polypeptides, effectively addressing stability and performance issues in industrial processes.
Implementation Method 1
Alpha-amylases (E.C. 3.2.1.1) constitute a group of enzymes which catalyze hydrolysis of starch, glycogen and related polysaccharides and oligosaccharides
Data Source
AI summary
The present invention relates to alpha-amylase variants with improved stability in the presence of glucose and/or relatively higher activity on long chain versus short chain substrates. The present encoding invention also relates to polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the variants.