蛋白质表达
BL21 StarTM(DE3):
F-ompThsdSB(rB-mB-)gal dcmrne131(DE3)
The two strains carry a mutated rne gene (rne131) which encodes a truncated RNase E enzyme that lacks the ability to degrade mRNA, resulting in an increase in mRNA stability.
蛋白质表达。
BL21（DE3）plysS
F- ompT gal dcm lon hsdSB（rB- mB-）λ（DE3）pLysS（cmR）
该菌株带有pLysS,具有氯霉素抗性。此质粒还有表达T7溶菌酶的基因，T7溶菌酶能够降低目的基因的背景表达水平，但不干扰IPTG诱导的表达。适合于毒性蛋白和非毒性蛋白的表达。
分子克隆、质粒提取和蛋白质表达。
JM109
endA1 glnV44 thi-1 relA1 gyrA96 recA1 mcrB+ Δ（lac-proAB）e14- [F' traD36 proAB+ lacIq lacZΔM15]hsdR17（rK-mK+）。
部分抗性缺陷，适合重复基因表达，可用于M13克隆序列测定和蓝白斑筛选。
用于真核蛋白表达（表达稀有密码子）
分子克隆、质粒提取和蛋白质表达。
BL21（DE3）
F- ompT gal dcm lon hsdSB（rB- mB-）λ（DE3 [lacI lacUV5-T7 gene 1 ind1 sam7 nin5）
该菌株用于以T7 RNA聚合酶为表达系统的高效外源基因的蛋白表达宿主。T7噬菌体RNA聚合酶基因的表达受控于λ噬菌体DE3区的lacUV5启动子，该区整合于BL21的染色体上。该菌适合于非毒性蛋白的表达。
BL21 Star (DE3)pLysS carries the pLysS plasmid which produces T7 lysozyme (see page 1). The BL21 Star (DE3) strain does not carry a plasmid expressing T7 lysozyme.
Rosetta™2 host strains are BL21 derivatives designed to enhance the expression of eukaryotic proteins thatcontain codons rarely used in E. coli. These strains supply tRNAs for 7 rare codones (AGA, AGG, AUA, CUA,GGA, CCC, and CGG) on a compatible chloramphenicol-resistant plasmid. The tRNA genes are driven by theirnative promoters.
The two strains are E. coli B/r strains and do not contain the lon protease. They are also deficient in the outer membrane protease, OmpT. The lack of these proteases reduces degradation of heterologous proteins expressed in the strains.
Expressing Heterologous Genes
BL21 StarTM(DE3)pLysS:
F-ompThsdSB(rB-mB-)gal dcm rne131(DE3) pLysS (CamR)
RosettaTM2 Competent Cells
F- ompT hsdSB(rB-MB-) gal dcm pRARE2 (CamR)
名称
Gene typeV44 thi-1 recA1 relA1 gyrA96 deoR nupG Φ80dlacZΔM15 Δ（lacZYA-argF）U169, hsdR17（rK-, λ-）
种常用于质粒克隆的菌株。其Φ80dlacZΔM15基因的表达产物与pUC载体编码的β-半乳糖苷酶氨基端实现α互补，可用于蓝白斑筛选。recA1和endA1的突变有利于克隆DNA的稳定和高纯度质粒DNA的提取。