RhtA Export Protein Variant for High-Yield L-Amino Acid Production

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Solution Overview

Problem

Existing methods for producing L-amino acids, such as L-homoserine and L-threonine, in microorganisms are not efficient enough to meet high-yield production demands.

Innovation Solution

A threonine/homoserine export protein variant is developed, where the amino acid at position 123 in the sequence is substituted with specific amino acids, and a microorganism expressing this variant is used to enhance L-amino acid production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional microorganisms with wild-type threonine/homoserine export protein are used, then the production process is simple, but the L-amino acid production yield is low

Engineering Contradiction:

ImproveL-amino acid production yieldVSAvoidprotein structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by substituting the amino acid at position 123 of the threonine/homoserine export protein with specific amino acids (Ala, Cys, Asp, Phe, Gly, His, Ile, Leu, Met, Ser, Thr, Trp, or Tyr). This single point mutation changes the protein's parameters to enhance its efflux activity, thereby improving L-amino acid production yield without significantly complicating the overall protein structure or production process

Inventive Principle:

Principle #35Parameter changes

2Productivity

If target material-specific approaches are used to increase expression of biosynthesis genes, then L-homoserine biosynthesis efficiency improves, but overall production capacity remains insufficient

Engineering Contradiction:

ImproveL-homoserine biosynthesis efficiencyVSAvoidproduction capacity limitation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies the extraction principle by focusing on and enhancing the specific function of the threonine/homoserine export protein (RhtA). Instead of attempting to optimize the entire biosynthetic pathway, the invention extracts and improves the key bottleneck step - the efflux of L-homoserine and L-threonine from the cell - by mutating position 123 of the export protein. This targeted approach removes the production capacity limitation by enhancing product export efficiency

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentEP4656651A1Variants of threonine/homoserine efflux protein and l-amino acid production method using same

Publication Date: 2025.12.03 CJ CHEILJEDANG CORP

AI summary

Provided are a threonine/homoserine export protein variant, and a method of producing an L-amino acid using the same.