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Isolation of Z-DNA-containing plasmids
Summary
Researchers developed a Z-DNA antibody column to purify plasmid DNA. This method successfully isolated Z-DNA containing plasmids from Escherichia coli DNA libraries, revealing natural Z-DNA conformations in E. coli.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- The Z-form of DNA is a left-handed double helix distinct from the common B-form.
- Identifying and isolating DNA sequences that adopt Z-DNA conformation in vivo is challenging.
Purpose of the Study:
- To develop a method for isolating and purifying plasmid DNAs containing Z-DNA.
- To investigate the presence of Z-DNA forming sequences in Escherichia coli.
Main Methods:
- Covalent coupling of a monoclonal antibody specific for Z-DNA to Sephacryl S-1000 beads.
- Affinity chromatography using the antibody-coupled beads to purify Z-DNA containing plasmids.
- Screening of an Escherichia coli DNA library cloned into pUC-8 vector.
Main Results:
- An antibody-based affinity column was successfully created for Z-DNA purification.
- Several recombinant plasmids containing Z-DNA binding sequences were isolated from an E. coli DNA library.
- These findings demonstrate that E. coli possesses DNA sequences capable of adopting a Z-DNA conformation.
Conclusions:
- Monoclonal antibody-coupled affinity columns offer an efficient method for Z-DNA purification.
- Escherichia coli harbors naturally occurring DNA sequences that can adopt a left-handed Z-DNA conformation under physiological conditions.