UNIT 2.4 Preparation of Genomic DNA from Bacteria
Published Online: 1 NOV 2001
Copyright © 2003 by John Wiley and Sons, Inc.
Lab Protocol Title
Current Protocols in Molecular Biology
How to Cite
Wilson, K. 2001. Preparation of Genomic DNA from Bacteria. Current Protocols in Molecular Biology. 00:2.4.1–2.4.5.
- Published Online: 1 NOV 2001
- Published Print: OCT 2001
Most protocols for the preparation of bacterial genomic DNA consist of lysis, followed by incubation with a nonspecific protease and a series of extractions prior to precipitation of the nucleic acids. Such procedures effectively remove contaminating proteins, but are not effective in removing exopolysaccharides which can interfere with the activity of enzymes such as restriction endonucleases and ligases. In this unit, however, the protease incubation is followed by a CTAB extraction whereby CTAB complexes both with polysaccharides and with residual protein, effectively removing both in the subsequent emulsification and extraction. This procedure is effective in producing digestible chromosomal DNA from a variety of gram-negative bacteria, all of which normally produce large amounts of polysaccharides. If large amounts of exceptionally clean DNA are required, the procedure can be scaled up and the DNA purified on a CsCl gradient, as described in the alternate protocol.