E.coli Origami (DE3)大腸桿菌表達宿主菌

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Origami host strains areK-12 derivatives that have mutations in both the thioredoxin reductase (trxB)and glutathione reductase (gor) genes, which greatly enhance disulfidebond formation in theE. colicytoplasm.Studies have shown that expression in Origami(DE3) yielded 10-fold more activeprotein than in another host even though overall expression levels weresimilar. The original Origami strains are compatible with ampicillin-resistantplasmids and are ideal for use with pET-32 vectors, since the thioredoxinfusion tag further enhances the formation of disulfide bonds in the cytoplasm.ThetrxBandgormutations areselectable on kanamycin and tetracycline, respectively; therefore, thesestrains cannot be used with plasmids that can only be selected with kanamycinor tetracycline. To reduce the possibility of disulfide bond formation betweenmolecules, strains containing mutations intrxBandgorare recommendedonly for the expression of proteins that require disulfide bond formation forproper folding.

DE3indicates thatthe host is a lysogen of λDE3, and therefore carries a chromosomal copy of theT7 RNA polymerase gene under control of thelacUV5promoter. Suchstrains are suitable for production of protein from target genes cloned in pETvectors by induction with IPTG.

Genotype:Δ(ara-leu)7697ΔlacX74 ΔphoA PvuIIphoR araD139ahpC galE galK rpsLF′[lac⁺lacI^qpro] (DE3)gor522::Tn10trxB(Kan^R,Str^R, Tet^R)