Pullulanase Variants Enhancing Thermoactivity via Specific Amino Acid Substitutions
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Solution Overview
Problem
Current pullulanase enzymes have limitations in thermoactivity, which affects their efficiency in starch conversion processes, particularly at higher temperatures.
Innovation Solution
Development of pullulanase variants with specific substitutions at positions such as 393, 143, 150, 243, 244, 346, 368, 370, 373, 381, 385, 387, 402, 429, 430, 456, 486, 492, 610, 631, 632, 665, and 699, enhancing their thermoactivity by maintaining at least 60% relative activity at 70°C compared to 65°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pullulanase enzymes are used in starch conversion processes at higher temperatures, then reaction speed and productivity increase, but enzyme activity and stability decrease
Solution Approach 1:
The patent applies parameter changes by modifying amino acid residues at specific positions (393, 143, 150, 243, 244, 346, 368, 370, 373, 381, 385, 387, 402, 429, 430, 456, 486, 492, 610, 631, 632, 665, and 699) in the pullulanase enzyme sequence. These substitutions alter the enzyme's physical and chemical properties, specifically enhancing its thermoactivity and stability at elevated temperatures while maintaining catalytic function.
Solution Approach 2:
The patent implements local quality by introducing specific amino acid substitutions at selected positions within the enzyme's three-dimensional structure. Rather than uniformly modifying the entire enzyme, targeted changes are made at specific locations that influence thermal stability and catalytic activity, allowing the enzyme to maintain functionality at higher temperatures.
2Reliability
If pullulanase variants with multiple amino acid substitutions are created, then thermoactivity and enzyme stability improve, but manufacturing complexity and development time increase
Solution Approach 1:
The patent applies preliminary action by pre-identifying and selecting specific amino acid positions (393, 143, 150, 243, 244, 346, 368, 370, 373, 381, 385, 387, 402, 429, 430, 456, 486, 492, 610, 631, 632, 665, and 699) that are most likely to influence thermal stability and catalytic activity. This预先 selection of target positions streamlines the protein engineering process by focusing mutagenesis efforts on key residues rather than attempting random or comprehensive modifications.
Solution Approach 2:
The patent systematically changes specific parameters (amino acid identities at defined positions) based on their predicted impact on enzyme performance. By establishing a defined set of substitutable positions with expected beneficial effects, the patent reduces the combinatorial complexity of variant development while still achieving improved thermoactivity through multiple substitutions.
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 exhibit improved thermoactivity, maintaining significant enzyme activity at elevated temperatures, enhancing their performance in starch conversion processes and fermentation product production.
Implementation Method 1
Pullulanase is a starch debranching enzyme having pullulan 6-glucano-hydrolase activity (EC3.2.1.41) that catalyzes the hydrolyzes the α-1,6-glycosidic bonds in pullulan, releasing maltotriose with reducing carbohydrate ends.
Implementation Method 2
The present invention provides pullulanase variants with improved properties compared to its parent, particularly increased thermoactivity.
Data Source
AI summary
The present invention relates to pullulanase variants comprising substitutions of the parent pullulanase at one or more positions corresponding to positions 393, 143, 150, 243, 244, 345, 346, 368, 370, 373, 381, 382, 385, 387, 402, 429, 430, 431, 432, 456, 486, 492, 610, 624, 631, 632, 665 and 699 of the polypeptide of SEQ ID NO: 3. The present invention also relates to polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the variants.