E. coli Protein Expression Strains

NEB offers several strains of competent E. coli for protein expression. Depending on your construct, there is a strain of E. coli that will optimally express your desired protein.

  • BL21(DE3) Competent E. coli (NEB #C2527), are chemically competent E. coli cells suitable for transformation and routine protein expression.
  • Lemo21(DE3) Competent E. coli (NEB #C2528) is a BL21(DE3) strain containing the Lemo System™, offering tunable expression of difficult clones.
  • NiCo21(DE3) Competent E. coli (NEB #C2529) are chemically competent E. coli cells derived from BL21(DE3). NiCo21(DE3) has been engineered to minimize E. coli protein contamination of IMAC fractions: endogenous GlmS is mutated to eliminate binding to IMAC resins, and three other proteins (SlyD, ArnA and Can) are tagged to enable rapid removal by chitin affinity chromatography.
  • NEBExpress Competent E. coli (High Efficiency) (NEB #C2523) are chemically competent E. coli cells suitable for high efficiency transformation and protein expression. They are the recommended host strain for the NEBExpress MBP Fusion and Purification System (NEB #E8201). NEBExpress E.coli does not restrict methylated DNA (McrA-, McrBC-, EcoBr-m-, Mrr-). NEBExpress Iq Competent E. coli (NEB #C3037) and BL21 Competent E. coli (NEB #C2530) strains may also be used with pMAL vectors or other vectors with a tac, trclac, or araBAD promoter.
  • The SHuffle® suite of competent E. coli was designed to encourage disulfide bond formation in expressed proteins. The SHuffle suite includes SHuffle Express Competent E. coli (NEB #C3028) SHuffle T7 Competent E. coli (NEB #C3026), SHuffle T7 Express lysY Competent E. coli (NEB #C3030) and SHuffle T7 Express Competent E. coli (NEB #C3029).
  • The T7 Express High Efficiency Group of Competent Cells includes three different strains, including T7 Express lysY/Iq Competent E. coli (High Efficiency) (NEB #C3013), T7 Express lysY Competent E. coli (High Efficiency) (NEB #C3010) and T7 Express Competent E. coli (High Efficiency) (NEB #C2566).

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E. coli Protein Expression Strains includes these subcategories:
T7 Expression
Non-T7 Expression
SHuffle Expression
FAQs for E. coli Protein Expression Strains
Protocols for E. coli Protein Expression Strains
Application Notes for E. coli Protein Expression Strains
    Publications related to E. coli Protein Expression Strains
    • Wagner, S., Klepsch, M., Schlegel, S., Appel, A., Draheim, R., Tarry, M., Hö, M., van Wijk, K.J., Slotboom, D.J., Persson, J.O. and de Gier, J. (2008) Tuning Escherichia coli for membrane protein overexpression Proc Natl Acad Sci U S A; 105 , 14371-14376 .
    • Anton, B.P., Fomenkov, A., Raleigh, E.A. and Berkmen, M. (2016) Complete Genome Sequence of the Engineered Escherichia coli SHuffle Strains and Their Wild-Type Parents Genome Announc; Mar 31;4(2), PubMedID: 27034504, DOI: 10.1128/genomeA.00230-16.
    • Lobstein, J., Emrich, C.A., Jeans, C., Faulkner, M., Riggs, P. and Berkmen, M. (2012) SHuffle, a novel Escherichia coli protein expression strain capable of correctly folding disulfide bonded proteins in its cytoplasm Microb Cell Fact; 11, 56. PubMedID: 22569138
    • Samuelson, J.C., Causey, T.B., and Berkmen, M. (2012) Disulfide-bonded protein expression in E. coli Genet Eng Biotechnol News; 32(3),
    • Leith, E.M., O'Dell, W.B., Ke, N., McClung, C., Berkmen, M., Bergonzo, C., Brinson, R.G., Kelman, Z (2019) Characterization of the internal translation initiation region in monoclonal antibodies expressed in Escherichia coli J Biol Chem; 294(48), 18046-18056.. PubMedID: 31604819, DOI: 10.1074/jbc.RA119.011008
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