3α-HSDH Mutants for UDCA Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing ursodeoxycholic acid (UDCA) face challenges such as incomplete conversion due to reaction equilibria and the need for multiple enzymes with different cofactor dependencies, leading to increased costs and complexity in the synthesis process.
Innovation Solution
Development of improved 3α-hydroxysteroid dehydrogenase (3α-HSDH) mutants from Comamonas testosteroni that can stereospecifically reduce dehydrocholic acid, allowing for enhanced activity and cofactor utilization, including the ability to use NADPH instead of NADH, and simultaneous or staggered reduction with 7β-HSDH, along with cofactor regeneration using dehydrogenases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple enzymes with different cofactor dependencies are used for UDCA synthesis, then the synthesis pathway can be completed, but the process complexity and costs increase
Solution Approach 1:
The 3α-HSDH enzyme from Comamonas testosteroni is engineered to accept both NADH and NADPH as cofactors, making it universally functional in positions that traditionally required multiple different enzymes. This multi-cofactor capability allows a single enzyme to perform functions that previously required multiple specialized enzymes, thereby simplifying the overall synthesis system while maintaining complete pathway functionality
2Productivity
If traditional 3α-HSDH is used for dehydrocholic acid reduction, then the reaction can proceed, but substrate inhibition limits conversion efficiency
Solution Approach 1:
The enzyme's kinetic parameters are modified through directed evolution and rational design to change its interaction with the substrate. Specifically, mutations are introduced that alter the enzyme's substrate binding characteristics and reduce inhibitory effects, thereby improving conversion efficiency without requiring changes to the overall reaction conditions or substrate concentration regimes
3Ease of manufacture
If NADH-dependent 3α-HSDH is used, then the enzymatic reduction can occur, but cofactor regeneration becomes more complex and costly
Solution Approach 1:
The 3α-HSDH enzyme is engineered with extended cofactor specificity to accept both NADH and NADPH. This universality provides flexibility in cofactor regeneration strategies, allowing the system to use whichever cofactor system is more economically viable or easier to regenerate in a given process configuration, thereby simplifying overall process design and reducing costs
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 improved 3α-HSDH mutants demonstrate increased specific activity and reduced substrate inhibition, enabling more efficient and cost-effective production of UDCA with improved cofactor utilization and simplified cofactor regeneration, thereby enhancing the UDCA synthesis process.
Implementation Method 1
3α-hydroxysteroid dehydrogenase mutants and process for the preparation of ursodeoxycholic acid
Implementation Method 2
The enzyme from C. testosteroni has proved to be a very suitable 3α-HSDH. The gene sequence of this enzyme is now known, so that firstly the enzyme can be made available recombinantly after cloning; secondly, it is possible to generate mutants of this enzyme by protein engineering methods
Data Source
AI summary
The invention provides novel 3α-hydroxysteroid dehydrogenase mutants, sequences that code for these enzyme mutants, methods for producing the enzyme mutants, and the use thereof in enzymatic reactions of cholic acid compounds, and in particular in the production of ursodeoxycholic acid (UDCA). The invention further provides processes for the synthesis of UDCA using the enzyme mutants and the production of UDCA using recombinant microorganisms that have been subjected to multiple modifications.