MilliporeSigma™ Novagen™ Rosetta™ 2(DE3)pLacI Competent Cells

Description

• 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
• Rosetta™ 2 strains are BL21 derivatives designed to alleviate codon bias when expressing heterologous proteins in E
• coli
• The cells carry a chloramphenicol-resistant plasmid with the tRNA genes that decode seven rare codons (AGA, AGG, AUA, CUA, GGA, CCC, and CGG) to improve the yield of full-length proteins
• The tRNA genes are driven by their native promoters
• In Rosetta 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.