Thermostable SAM Synthetase Mutants for Efficient Production
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Solution Overview
Problem
Current methods for producing S-adenosylmethionine (SAM) are inefficient due to the use of crude S-adenosylmethionine synthetase, which degrades ATP and methionine precursors, leading to high costs and contamination issues, and require optimization for increased activity and thermostability.
Innovation Solution
Development of thermostable and highly catalytic S-adenosylmethionine synthetase mutants through site-directed mutagenesis, specifically at positions 102, 93, and 357, which exhibit at least 70% higher catalytic activity than wild-type enzymes, allowing for efficient SAM synthesis at higher temperatures and reduced substrate degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If crude S-adenosylmethionine synthetase is used for SAM synthesis, then the enzyme can catalyze the reaction, but ATP and methionine precursors are degraded by other enzymes in the crude extract, leading to high production costs and contamination
Solution Approach 1:
The patent extracts and utilizes only the beneficial S-adenosylmethionine synthetase activity from the crude extract by employing specific mutants that exhibit high catalytic activity and thermostability, thereby eliminating the harmful degradation effects of other enzymes while maintaining ease of preparation through direct use of mutant enzymes
Solution Approach 2:
The patent applies parameter changes by conducting the enzymatic reaction at elevated temperatures (50-70°C) where the mutant S-adenosylmethionine synthetase maintains high activity while other degrading enzymes in crude extracts are denatured or inactivated, thus preventing substrate degradation without requiring pure enzyme preparation
2Ease of manufacture
If crude S-adenosylmethionine synthetase is used, then the enzyme preparation process is simple, but the reaction requires longer time and produces contaminated crude product requiring expensive separation and purification
Solution Approach 1:
The patent changes the temperature parameter to 50-70°C, which simultaneously achieves multiple benefits: the mutant enzyme maintains high catalytic activity, the reaction proceeds faster improving productivity, and the simplified preparation process remains effective because the mutant enzymes are inherently stable and do not require extensive purification
Solution Approach 2:
The patent employs a disposable approach by using thermostable mutant enzymes that can be used in single-use or limited-use scenarios at elevated temperatures without requiring recovery or repeated purification, thus maintaining ease of manufacture while achieving high productivity through the inherent stability and activity of the mutants
3Reliability
If wild-type S-adenosylmethionine synthetase is used, then the enzyme functions at standard temperature, but the catalytic activity is insufficient and reaction period is extended
Solution Approach 1:
The patent changes both temperature and enzyme structure parameters: the reaction temperature is elevated to 50-70°C and the enzyme is mutated to possess thermostability and enhanced catalytic activity, allowing the enzyme to function reliably at higher temperatures with improved productivity while maintaining functional stability
Solution Approach 2:
The patent creates a composite system by combining multiple mutant variants with different advantageous properties (thermostability, catalytic activity, substrate tolerance) into a optimized enzyme preparation that functions superiorly across multiple parameters compared to wild-type enzyme alone
4Productivity
If higher temperature is used for SAM synthesis, then substrate degradation is reduced and reaction efficiency improves, but the enzyme must tolerate heat treatment
Solution Approach 1:
The patent simultaneously changes the temperature parameter to elevated levels (50-70°C) and the enzyme structure parameter through site-directed mutagenesis to introduce thermostability, creating a matched system where the enzyme's thermal stability profile is optimized for the elevated reaction temperature, thereby achieving both improved productivity and maintained reliability
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 mutants maintain high activity at elevated temperatures, enabling cost-effective and purified SAM production by tolerating heat treatment, thus reducing production costs and reaction times while minimizing substrate degradation.
Implementation Method 1
S-adenosylmethionine synthetase (EC 2.5.1.6) catalyzes the synthesis of S-adenosylmethionine (S-Adenosyl Methionine, SAM or SAMe) from adenosine triphosphate (ATP) and methionine
Data Source
AI summary
The invention discloses a series of Methanococcus jannaschii S-adenosylmethionine synthetase mutants with improved thermostability and high catalytic activity obtained by using gene mutation technique, characterized in that these mutants refer to an enzyme using Sequence 2 in the Sequence Listing as the reference sequence and contains at least one mutation at position 102, position 93, position 230, and position 357 and has a catalytic activity at least 70% higher than that of the wild-type S-adenosylmethionine synthetase using adenosine triphosphate (ATP) and methionine as substrates. These S-adenosylmethionine synthetase mutants can be used in the production of S-adenosylmethionine.