Variant LysE Exporter for Higher L-Amino Acid Excretion
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Solution Overview
Problem
Existing methods for producing L-amino acids, particularly in Corynebacterium strains, face limitations in enhancing the production and export capabilities of L-amino acids, such as L-lysine and L-arginine, despite efforts to improve biosynthesis pathways.
Innovation Solution
Introduce a mutation in the lysine exporter protein (LysE) by substituting the 65th amino acid from the N-terminus, such as asparagine with another amino acid, to enhance the export and production capabilities of L-amino acids in microorganisms like Corynebacterium and Escherichia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the biosynthesis pathway of L-amino acids is improved through gene manipulation, then the production capability is enhanced, but the export capability remains limited
Solution Approach 1:
The patent applies parameter changes by mutating specific amino acid residues in the LysE protein structure (e.g., changing hydrophobic residues at positions 65, 68, 71 to hydrophilic residues like asparagine, glutamine, or serine). This structural parameter modification enhances the protein's export function, allowing more L-amino acids to be transported out of the cell, thereby resolving the contradiction between production capability and export capability.
2Reliability
If wild-type LysE is used for L-amino acid export, then the microorganism maintains normal function, but the export efficiency is insufficient for high-yield production
Solution Approach 1:
The patent applies local quality by making targeted mutations at specific local positions (amino acid residues 65-71) of the LysE protein while keeping the rest of the protein structure intact. This localized modification approach maintains the overall stability and reliability of the microorganism while significantly improving the export efficiency at the critical transport interface, thus resolving the contradiction between reliability and productivity.
Data Source
AI summary
Provided are a microorganism comprising variant LysE, and an L-amino acid producing method using same. The variant LysE may improve L-amino acid excretion and/or production capacity compared to a wild type.