Key to the kit is our proprietary DNA binding systems that allow the high efficient reversible binding of DNA to the mini column while proteins and other impurities are removed by wash buffer. Nucleic acids are then eluted with sterile water or elution buffer.
This kit is designed for fast and efficient purification of plasmid DNA from 1 to 4 mL of E. coli culture. The mini column has a plasmid DNA binding capacity of 50 µg. The yield from 1 mL culture is typically around 8 to 12 µg. Plasmid Miniprep Kit II (PD1213), with the plasmid DNA binding capacity of 80 µg, is recommended if higher yield (>50 µg) is desired.
The purified DNA is ready for downstream applications such as cloning/subcloning, RFLP, sequencing, and transfection of robust cells such as HEK293 cells.
Plasmid Copy Numbers: The yield of plasmid DNA depends on the origin of the replication and the size of the plasmid. The protocols are optimized for high copy number plasmid purification. For low copy number plasmids, both the culture volume and the buffer volume need to be scaled up 2 times. Please contact our customer service for further information and reference Table 1 for the commonly used plasmids.
Host Strains: The strains used for propagating plasmid have significant influence on yield. Host strains such as Top 10 and DH5a yield high-quality plasmid DNA. endA+ strains such as JM101, JM110, HB101, TG1 and their derivatives, normally have low plasmid yield due to either endogenous endonucleases or high carbohydrates released during lysis. We recommend transform plasmid to an endA- strain if the yield is not satisfactory. Please reference Table 2 for the endA information.
Optimal Cell Mass (OD600 x mL of Culture): This procedure is designed for isolating plasmid grown in standard LB medium (Luria Bertani) for 12 -16 hours to a density of OD600 2.0 to 3.0. If rich medium such as TB or 2xYT are used, make sure the cell density doesn't exceed 3.0 (OD600). A high ratio of biomass over lysis buffers result in low DNA yield and purity. The mini column has an optimal biomass of 10-15. For example, if the OD600 is 3.0, the optimal culture volume should be 1-5 mL. For over amount of cell numbers, either reduce the biomass or scale up the volumes of Buffer A1, B1 and N1.
Culture Volume: Use a flask or tube 4 times bigger in volume than the culture medium to secure optimal condition for bacteria growth. Don't exceed the maximum culture volume suggested in the protocol. Incomplete lysis due to over amount of bacterial culture results in lower yield and less purity.
Storage and Stability
Buffer A1 should be stored at 4°C once RNase A is added. All other materials can be stored at room temperature (22-25°C). The Guaranteed shelf life is 12 months from the date of purchase.
Prepare all components and get all necessary materials ready by examining this instruction booklet and become familiar with each steps and pay special attention to the followings,
- RNase A: 20 mg/mL. It is stable for more than half a year when stored at room temperature. Spin down RNase A vial briefly. Add the RNase A solution to Buffer A1 and mix well before use. Store at 4°C.
- Add 8 mL (PD1211-00) or 60 mL (PD1211-01) or 96 mL (PD1211-02) or 60 mL (PD1211-03) 96-100% ethanol to each DNA Wash Buffer bottle before use.
- Buffer B1 precipitates below room temperature. It is critical to warm up the buffer at 50°C to dissolve the precipitates before use.
- Keep the cap tightly closed for Buffer B1 after use.
- Ensure the availability of centrifuge capable of 13,000 rpm.
- Carry out all centrifugations at room temperature.
Materials supplied by user
- High speed microcentrifuge or Vacuum manifold.
- 96-100% ethanol.
- 1.5 mL microcentrifuge tubes
- Buffer N1 contains acidic acid, wear gloves and protective eyewear when handling.
- Buffer N1 and KB contains chaotropic salts, which may form reactive compounds when combines with bleach. Do not add bleach or acidic solutions directly to the preparation waste.