Protein Expression in Bacterial System

Bacterial protein expression systems are advantageous in several important ways, including their fast rate of reproduction, ease of culture, and production of recombinant protein with high yields. As they can grow to high densities with inexpensive media, bacteria are highly suitable for large-scale fermentations. E.coli is one of the most commonly used bacterial hosts in the production of heterologous proteins. It has been proven as the preferred system for laboratory investigations and initial development in commercial manufacture since there is ample knowledge about its genetics, genome sequence and physiology.

Backed by years of development and research experience in the field of recombinant protein expression, Biologics International Corp (BIC) offers comprehensive, high-quality recombinant custom protein services. All you need to do is simply provide protein sequences, and our experienced team of scientists will help you achieve your research goals quickly and efficiently. Contact us for project quotations and more detailed information. Learn more about our bacterial expression system.

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Service Highlights

  • Guaranteed: no-success no-fee guarantee.
  • Customization: quantity, purity, tags, and endotoxin levels are customizable and RNase removal is optional.
  • Modifications: isotope labeling, protein biotinylation and green fluorescent labeling services.

Bacterial Protein Expression Service

Service Process Deliverables
Bacterial protein expression

Design strategy

The optimal plan will be designed according to the customer’s requirements and protein characteristics.

  • Cloning vector
  • QC data
  • Final report
  • >90% purity
  • Quantity as per customer requirements (≥3 mg soluble proteins)
Bacterial expression system

Codon optimization
& gene synthesis
(2 weeks)

With our improved codon optimization technology, the expression levels of target proteins can be significantly improved.

Recombinant protein expression in Bacterial Expression System

Protein expression evaluation & optimization
(1 week)

We will conduct a series of pilot expression tests using diverse expression conditions and take SDS-PAGE and Western blot to confirm the expression levels. At this step, we will optimize your protein expression conditions.

Bacterial Protein Expression and Purification

Scale up & protein purification
(2-3 weeks)

We will scale up your protein expression using optimized conditions. According to your specific requirements, His, GST or other affinity tags are available. After multistep protein purification (affinity chromatography, ion-exchange chromatography, size-exclusion chromatography and hydrophobic interaction chromatography), the protein purity will be >90%. A tag-free protein service is also offered at the customer’s request.

Based on our customized solutions and extensive experience, we provide the following four optional services:

  • Endotoxin removal
  • As endotoxin interferes with biological responses, endotoxin removal is critical for in vivo and cell-based applications. BIC understands that a reliable and accurate endotoxin test and removal of endotoxin from your biological sample are extremely important for downstream applications. We offer an endotoxin removal service (detection levels below 1.0 EU/μg). Please contact us for more details.

  • Protein labeling
  • Protein labeling technique refers to the covalent attachment of molecules such as enzymes to specific sites on the target protein. BIC has developed a series of protein labeling techniques, including fluorescent probes (FITC), enzyme conjugates (horseradish peroxidase and alkaline phosphatase), isotope labeling and biotinylation.

  • RNase removal
  • Most lysis methods cause the release of RNA which may cause viscosity problems or interfere with subsequent steps, such as chromatography. Our RNase removal service will solve this problem.

  • Tag-free protein
  • Tags may have an impact on protein structure and biological functions. A recombinant protein with exogenous amino acids has a limited opportunity to pass the FDA approval. Efficient tag-free protein services offered by BIC generate high yields of tag-free protein with the desired amino acid sequence.

Related Services

Bacterial Protein Expression and Fermentation

Large Scale Protein Production

BIC’s large scale protein production services are available on any scale from 50 to 500 L for both fed-batch and continuous cultivation. You only need to provide the gene sequence of your target protein or the established vector, and we will begin the service as you have selected.

Bacterial protein expression service

Protein Interaction Analysis

Protein-protein interactions play a key role in predicting the protein function of the target protein and pharmaceutical properties of molecules. BIC provides three different methods of protein-protein interaction analysis, including GST pull-down, co-immunoprecipitation (CO-IP) and bio-layer interferometry (BLI), which will help you measure the affinity between proteins.

custom bacterial protein expression

Custom Antibody Production

Protein antigen have a complex structure which is closer to that of the native protein antigen when compared with the polypeptide antigens. Antibodies prepared with the protein antigens have higher specificity, higher titers, and excellent stability. Our services cover every step from antigen selection through antibody production. Meanwhile, we guarantee the delivery of antibodies with an ELISA titer of 1:128,000 or above.

If you have any questions, please contact us, and let us see what we can do for you.

Bacterial Expression Systems

Comparison of Other Expression Systems

Characteristics Mammalian Systems Bacterial Systems Yeast Systems
Cost High Low Low
Timeline Slow Fast Slow
Glycosylation Complex, authentic No Simple
Phosphorylation Yes No Yes
Acetylation Yes No Yes

Multi-domain eukaryotic proteins expressed in E.coli often fail to undergo the required post-translational modifications or molecular folding, resulting in loss of functions. E.coli has limited eukaryotic post-translational machinery function, which is considered as a key disadvantage when producing the eukaryotic phosphoproteins. Glycosylation is another complex process of post-translational modification. It is responsible for the formation of cellular glycans which are often attached to proteins and lipids. Glycoproteins, which are commonly distributed in eukaryotic cells, are rarely presented in prokaryotic organisms because cellular organelles essential for glycosylation are missing in these organisms. In addition, if you plan to use your recombinant proteins in animal cells, endotoxin will be a threat. In these cases, you may need endotoxin removal or a mammalian expression system.

Codon Optimization

Most of amino acids are encoded by more than one codon, heterologous genes with the codons which are rarely used in E.coli, may not be efficiently expressed, leading to translation errors. Translation errors arise from rare codon bias and include mistranslational amino acid substitutions, frameshifting events, or premature translational termination. Codon usage optimization and gene synthesis may improve the situation without any side effects.

Inclusion Bodies and Refolding

Inclusion bodies are the main problems when proteins are expressed in the cytoplasm. Cytoplasmic folding is often enhanced at low temperatures; thus, the use of cold temperature is often accompanied by misfolding and segregation into insoluble aggregates known as inclusion bodies. Aggregation can be minimized through the control of parameters such as temperature, expression rate and host metabolism. Though formation of inclusion bodies facilitates protein purification, there is no guarantee that the in vitro refolding will generate large amounts of biologically active products. If possible, protein refolding should be avoided.

Case Study

We have extensive experience in E.coli protein expression and provide highly purified active proteins in scales from large to small tailored to your needs. Download the PDF of our case study for more details.

Need more information? Please do not hesitate to get in touch.

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