MacB Transporter Enhances O-Phosphoserine Export Yield
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Solution Overview
Problem
Current methods for producing L-cysteine face challenges in achieving high yields due to limitations in efficiently exporting O-phosphoserine (OPS) from OPS-producing strains, necessitating the development of more effective transporters to enhance OPS production.
Innovation Solution
Identification and utilization of novel polypeptides, specifically YggT and MacB proteins with OPS exporting activity, to enhance the secretion of OPS from OPS-producing microorganisms, thereby increasing OPS production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional transporters (ydeD, yfiK, rhtB) are used to export OPS from OPS-producing strains, then some OPS secretion is achieved, but the export efficiency is insufficient to achieve high-yield OPS production
Solution Approach 1:
The patent applies parameter changes by modifying the transporter protein structure and function. Specifically, it identifies and utilizes the MacB protein (a member of the major facilitator superfamily) with enhanced OPS exporting activity compared to conventional transporters. The patent also employs mutated versions of transporters with improved export efficiency, directly changing the functional parameters of the transport system to achieve higher OPS production yields.
2Quantity of substance
If OPS-producing strain is cultured without efficient exporter, then OPS accumulates intracellularly, but extracellular OPS concentration remains low
Solution Approach 1:
The patent applies the extraction principle by introducing efficient exporter proteins (MacB and its mutated versions) that specifically extract OPS from the intracellular environment and transport it to the extracellular medium. This resolves the contradiction by providing a dedicated extraction mechanism that moves OPS from intracellular accumulation to extracellular secretion, thereby increasing both intracellular concentration during production and extracellular availability for recovery.
3Adaptability or versatility
If multiple transporter genes are screened and tested, then potential exporters are identified, but the process is time-consuming and complex
Solution Approach 1:
The patent applies preliminary action by pre-identifying and characterizing the MacB protein as an efficient OPS exporter before large-scale application. The patent performs preliminary screening and characterization work to identify MacB's superior export capability, then utilizes this pre-validated transporter in the OPS production system, avoiding the need for extensive screening processes in subsequent applications.
Data Source
Figure 1~2
AI summary
The present invention relates to a novel isolated polypeptide having the ability to export O-phosphoserine (OPS) that is a precursor of L-cysteine, a vector comprising the polynucleotide, an OPS-producing microorganism having enhanced activity of the polypeptide, a method of producing OPS using the microorganism, and a method for preparing cysteine or its derivatives, which comprises reacting OPS, produced by the above method, with a sulfide in the presence of O-phosphoserine sulfhydrylase (OPSS) or a microorganism that expresses OPSS.