E. coli Expression System

Introduction:

The E. coli expression system is regarded as the most commonly used, economical, and classical expression system because of its simple structure, clear genetic background, high yield of target protein, and its short culture period. In recent decades, E. coli expression system has also been developed and improved continuously, and been used intensively by scientific researchers and industrial users for a large number of recombinant protein expression. The system is mainly used for antigen preparation, ligand preparation, and expression of cytokines and bacteria (Staphylococcus aureus, Escherichia coli, etc.) proteins.

CUSABIO has extensive experience and be very professional in E. coli protein expression and purification. We can solve various difficult problems during the protein expression and purification process. From 2007 to 2017, we have successfully developed more than 4000 recombinant proteins expressed in E. coli, which contain hundreds of active proteins with high purity.

Please click here to view more active proteins: https://www.cusabio.com/catalog-37-1.html

Advantages:

• Clear genetic background
• Cost-effective, easy for large-scale production. Price as low as $535/1mg
• Short lead time
• Fast growth and high yield: as high as 200 mg/L
• More options for vectors and tags, higher success rate: as high as 99.1%
• Easy to optimize various conditions to achieve the best results

Guarantee:

Risk-free: We do NOT charge if we cannot deliver the protein.

Note: This risk-free custom protein service is only suitable for proteins within 800aa. We will charge according to different steps if you need to express proteins more than 800aa.

Service Process:

Steps	Project	Process		Cusabio Features	Lead Time
1	Plasmid construction	Codon optimization; gene synthesis		Multiple vectors optimization, More options for customers Optimize multiple vectors at the same time; Select the vector that has the highest yield, which can shorten lead time;	15-20 business days
		Restriction digestion of PCR products; Ligation to expression vector, e.g. Pcold-SUMO, pGEX-4T-1, pET22b-JT, etc.
		Transform TOP10 E.coil competent cells
		Obtain the correct recombinant plasmid
2	Transformation and strain screening	Transform the recombinant plasmid to host cells, e.g. BL21 (DE3), Rosetta-gami B (DE3) pLysS, C41 cells, culture overnight at 37℃		Multi-conditions optimization, multi-hosts selection In the small test, the temperature and IPTG are optimized to obtain the most suitable culture conditions. Multiple hosts are transformed at the same time to select the host bacteria with the highest yield.	5 business days
		Select single colony for small-scale induced expression; Detect protein expression by SDS-PAGE; Preserve the best colony.
		Optimize the expression conditions
3	Target protein expression and purification	1-10 L large-scale expression		Multiple purification methods (optional) Explore different chromatographic conditions including ion exchange, hydrophobic and others by using AKTA, and then determine the optimal purification method.	12-15 business days
		Protein purification
4	Inclusion body renaturation	Refolding if the target protein is inclusion body		Diverse refolding methods A variety of buffering conditions are used to quickly screen the best refolding buffer formula. Refolding protein with purity greater than 90% is obtained by dilution renaturation, dialysis renaturation, column chromatography renaturation and so on. Solubilization and refolding can be achieved for more than 95% of inclusion bodies.
5	Additional services (Optional)	Charge	Tag removal by restriction digestion	Flexible additional services Customers can flexibly choose from a variety of additional services to their specific needs, e.g. Endotoxin removal, Filter-sterilization, Tag removal, Lyophilization, etc. Some are complimentary, and some require additional charge.	3 business days
		Free	Filter-sterilization; Endotoxin removal; Lyophilization (Note: Lyophilization and Filter-sterilization can not be met simultaneously)		2 business days
6	Quality Control	Testing of purity, concentration, etc. QC report is provided.		Detailed COA report Detailed product data sheet and COA are provided for each project.	3-5 business days
Total lead time					35-45 business days