Summary of Issues Related to Proprotein Nuclear Expression Technology

2026-07-09

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After years of development, the E. coli recombinant protein expression technology has become a highly mature system compared to other expression systems. To achieve high-quality soluble proteins and high-yield expression in the E. coli expression system, an excellent expression strategy is essential. The experts at KMD Bioscience possess unique expertise and extensive knowledge in protein expression and antibody production; we strive to provide optimal solutions tailored to each client’s specific requirements.

Summary of Common Issues in Recombinant Protein Expression

Recombinant protein expression is never an overnight process, and no single approach works for every case. As shown in Table 1, we have summarized some common issues in protein expression technology and their corresponding strategies. For details on how to select host systems, expression plasmid systems, and culture systems for prokaryotic recombinant protein expression, please refer to our Prokaryotic Recombinant Protein Expression Services.

Table 1: Summary of Common Technical Issues and Strategies for E. coli Protein Expression Systems

Question	Possible Causes	Solutions
No or low protein expression	Before induction, the protein is toxic.	Controlling background expression levels: • For lac-based promoter expression, add glucose • Select a culture medium with glucose as the carbon source • For T7-based promoter expression, use a plasmid containing T7 lysosome • Use a strictly regulated plasmid to reduce the number of copies
	After induction, the protein is toxic.	Controlling the Level of Induced Expression: • Use an adjustable promoter • Use a strain with controllable induction • Reduce the copy number • Use a strain suitable for toxic protein expression • Employ a secretory expression strategy
	Codon Preference	Optimize plasmid DNA codons to match the host’s codon system Use codon-adjusted strains Increase biomass: • Try new culture media • Improve aeration conditions to prevent foaming
Inclusion Formation	Incorrect Disulfide Bond Formation	• Adopt a secretory expression strategy • Use E. coli strains with oxidizing cytoplasm
	Incorrect Folding	Co-express molecular chaperones Add culture medium containing compound chaperones and cofactors Remove the inducer and add fresh culture medium Reduce the expression rate: • Induce expression at a lower temperature • Adjust the inducer concentration
	Formation of Low-Solubility Proteins	•Modify the fusion partner protein to promote the expression of soluble proteins
	Critical post-translation editing is required	• Changing the expression host, such as switching from a prokaryotic to a eukaryotic expression system
The protein is inactive	Incorrect Folding	• Low-temperature-induced expression • Monitoring disulfide bond formation and folding in vitro
The protein is inactive	cDNA mutation	• Sequencing before and after plasmid-mediated expression induction • Use of recA− strains to ensure plasmid stability in the host • Changing the expression host, such as switching from a prokaryotic to a eukaryotic expression system

As a professional biotechnology service provider, KMD Bioscience is committed to providing clients with high-quality prokaryotic protein expression services. With state-of-the-art laboratory facilities and an experienced scientific team, we are able to offer customized prokaryotic protein expression solutions tailored to our clients’ needs. We utilize the latest gene cloning technologies and expression systems to ensure that target proteins are expressed efficiently and reliably in prokaryotic expression systems, followed by purification and functional characterization. Whether for small-scale laboratory research or large-scale industrial production, we are able to meet our clients’ needs and provide a high level of technical support and service assurance. By choosing KMD Bioscience’s prokaryotic protein expression services, clients can obtain high-quality protein samples that provide reliable support for advancements in their research and application fields.

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