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Invitrogen™ MultiShot™ StripWell BL21 Star™ (DE3) Competent Cells
Description
Includes
Box 1:
- MultiShot StripWell BL21 Star (DE3) Chemically Competent E. coli
- One rack of 12 strips x 8-tubes, 50μl per tube
Box 2:
- pUC19 DNA (10 pg/μl), 1 vial, 50 μl
- S.O.C. medium: 2 bottles, 15ml each
MultiShot StripWell BL21 Star (DE3) chemically competent E. coli cells are cloning competent cells designed for applications that require high-level expression of non-toxic recombinant proteins from low copy number, T7 promoter-based expression systems. Engineered to carry the λDE3 lysogen that contains the T7 RNA polymerase gene under control of the lacUV5 promoter, these cells are pre-aliquoted in a rack containing 12 strips of 8 wells to increase productivity for throughput bacterial transformations.
Enhanced expression of nontoxic recombinant proteins
The BL21 (DE3) E. coli strain is one of the most popular host strains to produce recombinant proteins and adapted in research or industrial applications. IPTG is required to induce expression of the T7 RNA polymerase cascade system that in turn transcribes the T7 promoter regulated target gene.
The BL21(DE3) strain is derived from the E. coli B strain that does not contain the lon protease and is also deficient in the outer membrane protease OmpT. The lack of two key proteases reduces degradation of heterologous proteins expressed in the strains. Additionally, several other strain features make them especially suited for protein production, namely fast growth in minimal medium, a lower acetate production when grown in high glucose media, and an ability to reach high cell density.
MultiShot StripWell BL21 Star (DE3) Competent Cells offer enhanced mRNA stability due to a mutation in the RNaseE gene (rne131) that reduces levels of endogenous RNases and mRNA degradation, thereby increasing the stability of mRNA transcripts and increasing protein yield. The BL21 Star strain has higher basal expression of heterologous genes than BL21 (DE3) strains, due to the increased stability of mRNA. Thus, strains such as BL21-AI are recommended for toxic protein expression.
One Shot BL21 Star (DE3) Chemically Competent E. coli offer:
• Transformation efficiency of >1 x 107 cfu/μg plasmid DNA
• Ion and OmpT protease deficiency that reduces degradation of recombinant protein
• Optimized for use with low copy number, T7 promoter-based plasmids
• rne131 mutation that reduces levels of endogenous RNases and mRNA degradation
• hsdS mutation that allows efficient transformation of unmethylated DNA
• Fast growth in minimal medium and ability to reach high cell density
MultiShot StripWell flexible format
Each StripWell of eight connected tubes is designed with the same single-tube, single-use features as our One Shot format tubes. This format allows all steps of the transformation protocol, up to plating, to take place in the same tube, thereby saving time and reducing chance of contamination. After addition of DNA, MultiShot StripWell competent cells can be transformed by heat-shock at 42°C using a water bath, all in the same tube.
The StripWell tubes can be easily cut to permit transformations in a single tube, eliminating wasted aliquots of cells and avoiding freeze-thaws that can result in reduced transformation efficiency.
Benefits of the MultiShot StripWell format include:
• Increased productivity—suitable for high throughput experimentation
• Maximal flexibility—transform as few as 1 tube or as many as 96 from the StripWell rack
• Familiar convenience—add DNA directly to cells, heat shock, and recover in the same tube
Genotype
F–ompT hsdSB (rB–, mB–) gal dcm rne131 (DE3)
Find the strain and format that you need
• We offer many E. coli strains and formats of chemically competent and electrocompetent cells to meet transformation needs.
• For high-throughput transformation, choose from our collection of MultiShot formatted comp cells.
• We offer a variety of systems for the expression of recombinant proteins in E. coli.
Specifications
Specifications
| Product Type | Chemically Competent Cells |
| Contains F' Episome | No |
| Cloning Methylated DNA | No |
| Content And Storage | • MultiShot StripWell BL21 Star (DE3) Competent Cells (1 x 96-well plate at 50 μL/well); store at –80°C • pUC19 DNA (50 μL at 10 pg/μL); store at –20°C • S.O.C. Medium (2 x 15 mL); store at 4°C or room temperature |
| Antibiotic Resistance Bacterial | No |
| Blue/White Screening | No |
| High-throughput Compatibility | High |
| Preparing Unmethylated DNA | Yes (dcm) |
| Reduces Recombination | No |
| Shipping Condition | Dry Ice |
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Frequently Asked Questions (FAQs)
There are situations where either because of time or process limitations, elimination of the heat shock and recovery time post-heat shock in the transformation protocol would be desirable. Testing was performed on many of our chemically competent cells in both the MultiShot StripWell and MultiShot FlexPlate format with a shortened transformation protocol. Use of a rapid transformation protocol (add DNA, no heat shock, no recovery period, plate on warm agar) yielded up to a log lower in transformation efficiency using the control DNA. This rapid transformation protocol can be performed with expectation of lower colony counts than our standard high efficiency transformation protocol and can only be performed with plasmids that use ampicillin as their antibiotic resistance. The rapid protocol is ideal when using a liquid handling system for high-throughput transformations with high cloning efficiency. Please see the product manual for full details on this rapid transformation protocol option.
The MultiShot FlexPlate is a PCR plate and can be placed in a thermal cycler or heat block set at 42 degrees C to transform the cells by the heat shock method. The duration of the heat shock performed in these devices has yielded similar transformation efficiencies as that seen with heat shock done in a water bath.
We offer the following E. coli strains in the MultiShot StripWell format: TOP10, DH5alpha T1R, Mach1 T1R, Stbl3, and BL21 Star (DE3) chemically competent cells.
We offer the following E. coli strains in the MultiShot FlexPlate format: TOP10, DH5alpha T1R, DH10B T1R, Mach1 T1R, OmniMAX2 T1R, and Stbl3 chemically competent cells.
The MultiShot StripWell format is supplied as pre-aliquoted competent cells in 96 tubes contained in a rack. The tubes are attached in strips of 8 tubes, and there are 12 strips that contain 50 µL of chemically competent cells. This format offers the most flexibility to transform 1 tube or up to all 96 tubes at once and is intended for varied or medium-throughput use.
The MultiShot FlexPlate format is supplied as pre-aliquoted competent cells in a 96-well PCR plate. Each well contains 20 µL of competent cells. The plate can be separated at each column of 8 wells, offering a high level of flexibility to utilize various increments of 8 wells per transformation. The wells of the plate are heat sealed, preventing detachment of the aluminum seal in the -80 degrees C freezer and preventing contamination. This format is compatible with automated liquid handling platforms and is intended for medium- to high-throughput use.
The MultiShot format is supplied as pre-aliquoted competent cells in 5, 96-well thin-wall polycarbonate microplates. Each well of the 96-well microplate contains 15 µL of chemically competent cells. This format is compatible with automated liquid handling platforms and is intended for high-throughput use.
For Research Use Only. Not for use in diagnostic procedures.