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OverExpress™ C41(DE3) and C43(DE3) Competent Cells

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Cat.No.: 60341, 60345, 60442, 60444, 60448, 60452,

Products Description

E. cloni® OverExpressTM 特色        

1) OverExpress是唯一專門針對表現毒蛋白及膜蛋白而選擇出來的勝任細胞。
2) 超過350 篇表達毒性蛋白之publications驗證,成功案例包含來自於Mammal, Plant, Yeast, Virus...蛋白


專門為表達toxic (毒蛋白) 和 membrane proteins (膜蛋白) 而開發的勝任細胞 
  BL-21(DE3)雖然是目前最常使用來表達的E. coli,但並非所有的蛋白都可以表現,在挑選蛋白質表現的clones時失敗的原因,常與大量表現的蛋白質會造成細胞虛弱甚至死亡有關。尤其是膜蛋白、 nucleases之類的蛋白質。Lucigen經由大量篩選mutants的方法,找到獨家的兩個抗蛋白質毒性的DE3 strains: C41(DE3) 及C43(DE3)。其中C41(DE3)是由BL21(DE3) mutants中選出來的,這一個strain包含了至少一個阻止細胞在表現毒蛋白時死亡的基因突變。而C43(DE3) 則是經由在C41(DE3)細胞中表現另外一組不同的有毒性的蛋白質而挑選出來的。因此這兩種品系對表達不同種類的毒蛋白具有抗性,使E. coli在表達毒蛋白時不會影響其存活率或蛋白產量。目前已有超過350篇papers見證這兩株OverExpressTM strains在表現毒蛋白及膜蛋白上的有效性。OverExpress C41(DE3) pLysS and C43(DE3)pLysS 多了一個表現T7 Lysozyme的基因。T7 Lysozyme可抑制T7 promoter,因此更可以避免toxic proteins在未IPTG induction時就有的微量的表達。
 

 

Figure 1. Green Fluorescent Protein (top) or Red Fluorescent Protein (bottom) expressed from a T7 promoter construct that was transformed into C41, BL21, or C43 competent cells spread on IPTG plates to induce protein expression.

Table 1 and Figure 2 summarize transformation effectiveness, tolerance of expression-induced toxicity, and protein expression for T7 expression plasmids coding for a variety of recombinant proteins. These results demonstrate that the OverExpress C41(DE3) and C43(DE3) strains are clearly superior to the parental BL21(DE3) in transformation and expression of toxic proteins.

Table 1. Comparison of OverExpress C41(DE3) and C43(DE3) cells with the parental strain BL21(DE3) in transformation and expression of heterologous proteins.


Figure 2. Comparison of OverExpress C41(DE3) and C43(DE3) cells with the parental strain BL21(DE3) in transformation and expression of heterologous proteins.

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