Many promoter systems have been developed where target gene transcription relies on the endogenous E. coli RNA polymerase. For example, IPTG-inducible promoters include the wt-lac promoter and the tac and trc promoters are lac derivatives with greater induction potential. The phage T5 promoter is also recognized by E. coli RNA polymerase: vectors employing the T5-lacO promoter include a lac operator site for expression control by the lac repressor. T5-lacO vectors typically do not encode the lacI repressor gene and therefore the expression host must supply the lac repressor. NEB Express Iq was designed specifically for IPTG-inducible vector systems where the lacI gene is not encoded by the vector.
The NEB Express strain is a multiple purpose expression strain capable of robust expression from lac, tac, trc, arabinose-inducible and rhamnose-inducible promoters. Importantly, NEB Express is recommended as the host for any pMAL vector designed for MBP-fusion protein expression
Avoid Common Obstacles in Protein Expression
Read how to avoid common obstacles in protein expression that prevent interactions with cellular machinery.
- Competent Cell Brochure
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- Agrawal, A., Bisharyan, Y., Papoyan, A, Bednenko, J., Cardarelli, J., Yao, M., Clark, T., Berkmen, M., Ke, N., Colussi, P. (2019) Fusion to Tetrahymena thermophila granule lattice protein 1 confers solubility to sexual stage malaria antigens in Escherichia coli. Protein Expr Purif; 153, 7-17. PubMedID: 30081196, DOI: 10.1016/j.pep.2018.08.001.
- Manta, Bruno; Berkmen, Mehmet; (2019) Disulfide Bond Formation in the Periplasm of Escherichia coli. EcoSal Plus; PubMedID: 30761987, DOI: 10.1128/ecosalplus.ESP-0012-2018.
- Ke, Na; Berkmen, Mehmet; Ren, Guoping; (2017) A water-soluble DsbB variant that catalyzes disulfide-bond formation in vivo Nat Chem Biol; 13, 1022-1028. PubMedID: 28628094, DOI: 10.1038/nchembio.2409
- Hemmis, C.W., Berkmen, M., Eser, M.and Schildbach, J.F. (2011) TrbB from conjugative plasmid F is a structurally distinct disulfide isomerase that requires DsbD for redox state maintenance. J Bacteriol; 193(18), 4588-97. PubMedID: 21742866, DOI: 10.1128/JB.00351-11
- Shouldice, S.R., Cho, S.H., Boyd, D., Heras, B., Eser, M., Beckwith, J., Riggs, P., Martin, J.L.and Berkmen, M. (2010) In vivo oxidative protein folding can be facilitated by oxidation-reduction cycling. Mol Microbiol; 75(1), 13-28. PubMedID: 19968787
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