Linear pBR322 DNA

• High-purity linear pBR322 DNA prepared from the well-characterised pBR322 plasmid – ideal for topoisomerase and DNA repair studies
• Precisely linearised substrate produced by restriction enzyme digestion and validated for full conversion from the supercoiled form
• Designed for use in DNA cleavage, ligation, recombination, and topoisomerase II ATPase activity assays
• Provides a defined control substrate for comparison with supercoiled and relaxed plasmid DNA
• Supplied at a concentration of 1 mg/ml in TE buffer (10 mM Tris-HCl, pH 7.5, 1 mM EDTA) for stability and compatibility with standard assay conditions
• Ready-to-use in decatenation, relaxation, or linearisation experiments – no additional preparation required
• Produced under stringent quality control to ensure reproducibility and batch-to-batch consistency
• Compatible with fluorescence, gel-based, and biophysical detection methods
• Supports research into DNA topology, enzyme kinetics, and mechanistic inhibitor screening
• Store at 4°C for reliable long-term stability and consistent performance

Linear pBR322 DNA is a precisely linearised plasmid DNA substrate prepared to high purity for use in DNA topology and enzyme activity studies. It provides a well-defined reference material for assays involving DNA topoisomerases, nucleases, ligases and other DNA-modifying enzymes.

Preparation and quality

Our linear plasmid DNA is derived from a high-copy derivative of pBR322 and produced using the large-scale alkaline lysis method (Sambrook et al., 1989) from E. coli. The purified plasmid is then linearised by digestion with HindIII (EcoRI can also be used), ensuring complete conversion of the circular plasmid to linear DNA. The DNA is subsequently concentrated and repurified to remove residual enzyme and buffer components.

Each batch of linearised pBR322 DNA is validated for integrity, concentration and purity, ensuring consistent performance in biochemical and molecular assays. This preparation provides a reliable substrate for comparison with supercoiled or relaxed pBR322 forms.

Product format

Linear DNA is supplied at a concentration of 1 mg/ml in TE buffer (10 mM Tris-HCl, pH 7.5, 1 mM EDTA). This buffer maintains DNA stability and integrity during storage and repeated use.

Applications

• Substrate for topoisomerase II or IV ATPase assays
• Control DNA in relaxation and decatenation experiments
• Reference material for linear versus supercoiled plasmid DNA comparison
• Studies of DNA cleavage, ligation and recombination
• Educational or training use in molecular biology

Storage and stability

Store linearised DNA at 4°C. The preparation is stable under these conditions and suitable for long-term laboratory use.

Our linear pBR322 plasmid DNA combines precise linearisation with exceptional purity and consistency, providing researchers with a dependable substrate for studying DNA topology, enzyme mechanisms and nucleic acid interactions across a wide range of experimental systems.

FAQs About Linear pBR322 DNA

What is linear pBR322 DNA?
Linear pBR322 DNA is a purified plasmid DNA that has been linearised by enzymatic digestion. It provides a well-defined DNA substrate for studying enzyme mechanisms, including cleavage, ligation, recombination and relaxation.

How is the linear plasmid DNA produced?
The plasmid is first isolated from a high-copy derivative of pBR322 using the large-scale alkaline lysis method described by Sambrook et al. (1989). It is then digested with the restriction enzyme HindIII to produce completely linearised DNA, followed by purification and concentration to remove residual enzyme and contaminants.

What is the concentration and buffer composition?
Linear pBR322 DNA is supplied at a concentration of 1 mg/ml in TE buffer (10 mM Tris-HCl, pH 7.5, 1 mM EDTA). This buffer maintains DNA stability and prevents degradation during storage.

What are the main applications of linear plasmid DNA?
Typical applications include:

• Substrate for ATPase assays involving DNA topoisomerases II and IV
• Comparison with supercoiled or relaxed pBR322 DNA in enzymatic studies
• Control DNA for cleavage or ligation reactions
• Research into DNA recombination and repair mechanisms
• Teaching and training in molecular biology techniques

How should linear DNA be stored?
Store linearised pBR322 DNA at 4°C. The DNA remains stable under these conditions for extended use. Avoid repeated freeze–thaw cycles to preserve integrity.

Is the DNA fully linearised?
Yes. Each batch is verified for complete linearisation and purity using agarose gel electrophoresis, ensuring consistent quality across experiments.

Can other forms of pBR322 DNA be ordered?
Yes. Supercoiled, relaxed and positively supercoiled forms of pBR322 DNA are also available, allowing researchers to compare enzyme activity across different DNA topologies.