Mannanase PMan5A Mutants for Enhanced Thermal Stability
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Solution Overview
Problem
Existing endo-β-mannanases have limited application due to poor thermal tolerance and low catalytic activity, which restricts their use in extreme environments and efficient substrate affinity.
Innovation Solution
Site-specific mutations at positions 93, 94, 356, and 389 of the β-mannanase PMan5A, such as substituting H, F, L, or A with Y, H, or P, to create mutants with improved thermal stability and catalytic activity, including single-site, double-site, and multiple-site combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If site-specific mutations are introduced to improve thermal stability, then thermal tolerance is enhanced, but enzyme structure complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically mutating specific amino acid positions (93, 94, 356, 389) to different residues (Y, H, P) to optimize thermal stability. This involves changing the chemical parameters of the enzyme structure at key positions to achieve improved temperature tolerance while maintaining catalytic function.
Solution Approach 2:
The invention implements local quality by focusing mutations on specific critical positions within the enzyme structure rather than random modifications. The four selected positions (93, 94, 356, 389) represent key local regions that, when modified, produce significant thermal stability improvements with minimal overall structural changes.
2Productivity
If multiple-site combination mutations are performed to enhance catalytic activity, then enzyme efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the enzyme optimization into distinct mutation positions (93, 94, 356, 389) that can be independently modified and tested. This allows systematic evaluation of single-site and combination mutations, enabling rational design of high-activity variants without requiring complete redesign of the entire enzyme.
Solution Approach 2:
The invention uses composite materials principles by combining multiple amino acid substitutions at different positions to create enzyme variants with synergistic effects. The combination mutations (e.g., H93Y/F94Y/L356H/A389P) integrate multiple local modifications to achieve superior catalytic activity that exceeds individual mutations.
Data Source
AI summary
The present invention relates to a mannanase PMan5A mutant having improved heat resistance, a gene encoding the mutant and application thereof. The mutant is obtained by a substitution of histidine with tyrosine at amino acid residue 93, phenylalanine with tyrosine at amino acid residue 94, leucine with histidine at amino acid residue 356, and/or alanine with proline at amino acid residue 389. The thermal tolerance of the single site mutation mutant H93Y, L356H and A389P are greatly improved over that of the wild-type mannanase PMan5A, and the thermal tolerance of the combination mutants shows the stack effect of the single site mutation, demonstrating the amino acids at the sites of 93, 94, 356, and 389 play an important role for the thermal stability of the mannanase of GH5 family.