Expression of heterologous proteins presents many challenges. In E. coli, expression of a non-native protein often adversely affects the viability of the host cell both during the transformation stage and during protein expression. To improve host viability and consequently improve the potential for target protein over-expression, well-regulated expression systems should be employed. In E. coli expression systems, regulation is often provided by the host cell as well as the expression vector. IPTG-inducible systems rely on the Lac repressor to bind to lac, tac, trc or T7-lac promoters to inhibit expression until the culture reaches an optimal density for induction. In T7 systems, the Lac repressor is also important but an even more effective means to control expression is to employ a host strain that expresses a T7 RNA polymerase inhibitor protein (e.g. LysY).
- 5 Minute Transformation Protocol (C2528)
- 5 Minute Transformation Protocol (C3010)
- 5 Minute Transformation Protocol (C3013)
- 5 Minute Transformation Protocol (C3016)
- Analysis of Synthesized Protein using PURExpress (E6800)
- Determination of Protein Synthesis Yield with PURExpress (E6800)
- Expression Using SHuffle (C3026)
- High Efficiency Transformation Protocol
- High Efficiency Transformation Protocol (C3013)
- High Efficiency Transformation Protocol (C3016)
- Measurement of 35S-Methionine Incorporation by TCA Precipitation and Yield Determination using PURExpress
- Protein Expression Using Lemo21(DE3) (C2528)
- Protein Expression with T7 Strains
- Protein Synthesis Reaction using PURExpress (E6800)
- Protocol for Expression Using T7 Express Iq (C3016)
- Protocol for Expression Using T7 Express lysY (C3010)
- Protocol for Expression Using T7 Express lysY/Iq (C3013)
- Purification of Synthesized Protein using Reverse His-tag Purification
- Transformation Protocol (C2528)
The Future of Cell-Free Protein Synthesis
Cell-free protein synthesis has the potential to become one of the most important high throughput technologies for functional genomics and proteomics.
Avoid Common Obstacles in Protein Expression
Read how to avoid common obstacles in protein expression that prevent interactions with cellular machinery.
Competent Cells Brochure
The Competent Cells brochure provides information on the different competent cell strains for cloning and protein expression available from NEB.
Protein Expression & Purification Brochure
The Protein Expression and Purification brochure provides information on the advanced tools for protein expression and purification offered by NEB.
- DNA Sequences and Maps Tool
- Competent Cell Product Comparison
- Protein Expression and Purification Selection Chart
- Convenient Formats of Competent Cells
E. coli Hosts
Disulfide Bond Formation
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This product is intended for research purposes only. This product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.
NEB has a long history in recombinant protein expression and has developed a wide array of solutions for proteins that are difficult to express.