Mutant 3-HBDH Enzyme Thermal Stability and Substrate Affinity
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Solution Overview
Problem
Current 3-hydroxybutyrate dehydrogenase (3-HBDH) enzymes from Rhodobacter sphaeroides have low thermal stability and limited affinity for substrates and cofactors, making them unsuitable for robust and sensitive diagnostic applications, particularly in monitoring insulin therapy and diagnosing diabetes-related ketone body imbalances.
Innovation Solution
Development of mutant 3-HBDH enzymes with specific amino acid substitutions, such as at positions 250, 232, and 144, which enhance thermal stability and substrate/cofactor affinity, allowing for improved performance in converting 3-hydroxybutyrate to acetoacetate, even under stressful conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild-type 3-HBDH is used, then the enzyme can catalyze the conversion of 3-hydroxybutyrate to acetoacetate, but the thermal stability and substrate/cofactor affinity are insufficient for robust diagnostic applications
Solution Approach 1:
The patent applies parameter changes by systematically modifying amino acid sequences of 3-HBDH through site-directed mutagenesis. Specific amino acid positions (e.g., 250, 232, 144) are targeted for substitution to optimize thermal stability and substrate affinity while preserving catalytic function. This approach transforms the enzyme's physical and chemical parameters to achieve improved performance in diagnostic applications.
Solution Approach 2:
The patent implements local quality by introducing specific amino acid substitutions at particular positions within the enzyme structure rather than global modifications. Mutations at specific sites (e.g., position 250 with Met or Ile substitution) locally enhance thermal stability and substrate binding affinity while maintaining the overall enzyme structure and catalytic mechanism intact.
2Reliability
If multiple amino acid substitutions are introduced to improve thermal stability and affinity, then enzyme performance increases, but the complexity of enzyme production and characterization increases
Solution Approach 1:
The patent applies segmentation by dividing the enzyme optimization process into distinct stages: first identifying beneficial single mutations, then systematically combining them in controlled pairs and groups. This segmented approach allows for manageable production and characterization of mutants with defined amino acid substitutions, reducing overall complexity compared to random multiple mutations.
Solution Approach 2:
The patent implements preliminary action by pre-identifying and validating individual amino acid substitutions that improve enzyme performance before combining them. The systematic screening and characterization of single mutants first establishes a foundation of known beneficial changes, making subsequent combination experiments more predictable and less complex.
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 3-HBDH enzymes demonstrate increased stability and affinity, leading to enhanced diagnostic capabilities for monitoring 3-hydroxybutyrate levels, improving the accuracy and reliability of ketone body metabolism assessments in clinical settings.
Implementation Method 1
3-hydroxybutyrate dehydrogenase (3-HBDH) with improved performance relative to the wild-type 3-HBDH... converting 3-hydroxybutyrate to acetoacetate
Data Source
AI summary
The present invention relates to a mutant 3-hydroxybutyrate dehydrogenase (3-HBDH) with improved performance relative to the wild-type 3-HBDH, a nucleic acid encoding the mutant 3-HBDH, a cell comprising the mutant 3-HBDH or the nucleic acid, a method of determining the amount or concentration of 3-hydroxybutyrate in a sample, and a device for determining the amount or concentration of 3-hydroxybutyrate in a sample.