Recombinant L-Amino Acid Strains With Targeted Gene Mutations
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Solution Overview
Problem
Current methods for producing L-amino acids, such as L-lysine and L-glutamic acid, are limited in efficiency and require improvements in genetic engineering to enhance production capacity.
Innovation Solution
Modifying specific genes, such as NCgl0609 and NCgl1575, through point mutations and enhancing their expression, along with altering promoter sequences, to increase the production capacity of L-amino acids in microorganisms like Corynebacterium glutamicum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct fermentation method is used with complete biosynthetic pathway strains, then L-lysine production can be achieved, but production efficiency is limited
Solution Approach 1:
The patent applies parameter changes by introducing point mutations at specific positions (C1000T in NCgl0609 gene, A1775T in NCgl1575 gene) to alter enzyme activity and metabolic flux. These precise nucleotide substitutions change the biochemical parameters of key enzymes in the L-lysine biosynthetic pathway, thereby improving production efficiency without requiring complex genetic engineering approaches
Solution Approach 2:
The patent segments the L-lysine production optimization into targeted gene modifications rather than whole-pathway engineering. By focusing on specific genes (NCgl0609 and NCgl1575) and their critical mutation points, the approach divides the complex biosynthetic pathway into manageable segments for independent optimization, reducing overall engineering complexity
2Productivity
If gene expression is enhanced through mutation, then L-amino acid production increases, but strain development time increases
Solution Approach 1:
The patent employs preliminary action by pre-identifying and introducing specific point mutations (C1000T and A1775T) that have been shown to enhance gene expression and L-amino acid production. Rather than conducting extensive screening and evolution experiments, the predetermined mutations are directly introduced into the strain, significantly reducing the time required for strain development while achieving high production capacity
Solution Approach 2:
The patent uses parameter changes through specific nucleotide substitutions that alter gene expression levels and enzyme activity. The C1000T mutation in NCgl0609 and A1775T in NCgl1575 change the biochemical parameters of these genes, leading to enhanced L-amino acid production without requiring lengthy strain optimization processes
Data Source
AI summary
A bacterium for producing L-amino acid has improved expression of a polynucleotide encoding a protein represented by SEQ ID NO: 3 and improved expression of a polynucleotide encoding a protein represented by SEQ ID NO: 31, and/or has mutations in bases at positions −45 bp and −47 bp of a promotor region represented by SEQ ID NO: 57. A polynucleotide, encodes proteins and can be included in a recombinant vector, which can be included in a recombinant strain. These are useful in a method for producing L-amino acid. The polynucleotide encodes a protein which is represented by SEQ ID NO: 3 and has arginine at position 334 substituted by a terminator or encodes a protein which is represented by SEQ ID NO: 31 and has tyrosine at position 592 substituted by phenylalanine, or is formed by mutations in bases at positions −45 bp and −47 bp of a promotor region represented by SEQ ID NO:57.