71347  Origami™ 2(DE3)pLacI Competent Cells

Expression host strains for pETBlue™ and pTriEx™ vectors are lDE3 lysogens that also carry the compatible pLacI plasmid, encoding the lac repressor. The pLacI plasmid confers chloramphenicol resistance and provides enough lac repressor to inhibit transcription from the T7lac promoter in the absence of inducer. The NovaBlue host strain is recommended for initial cloning with pETBlue and pTriEx vectors due to its superior transformation efficiency and high yields of high-quality plasmid DNA.

Note that these strains are not recommended for use with pET, pACYCDuet™, pCDF, pRSF, pCOLADuet™ or pETcoco™ vectors.

.Origami 2 host strains are K-12 derivatives that have mutations in both the thioredoxin reductase (trxB) and glutathione reductase (gor) genes, which greatly enhance disulfide bond formation in the cytoplasm. Unlike the original Origami strains, the Origami 2 strains are kanamycin sensitive; like the original strains, the gor mutation is still selected for by tetracycline. To reduce the possibility of disulfide bond formation between molecules, hosts containing the trxB/gor mutation are recommended only for the expression of proteins that require disulfide bond formation for proper folding. In Origami 2(DE3)pLacI, the rare tRNA genes are present on the same plasmid that carries the lac repressor gene.

DE3 indicates that the host is a lysogen of λDE3, and therefore carries a chromosomal copy of the T7 RNA polymerase gene under control of the lacUV5 promoter. Such strains are suitable for production of protein from target genes cloned in pET vectors by induction with IPTG. Genotype: Δ(ara-leu)7697 ΔlacX74 ΔphoA PvuII phoR araD139 ahpC galE galK rpsL F′[lac⁺ lacI^q pro] (DE3) gor522::Tn10 trxB pLacI (Cam^R, Str^R, Tet^R)