Hi,
I obtained the this explanation from : https://bitesizebio.com/180/the-basics-how-alkaline-lysis-works/
You can check the sites for complete answer:
The acidic acetate buffer neutralizes the solution and allows the plasmids to renature. Under these conditions, the hydrogen bonding between the bases of the single stranded DNA can be re-established, so the ssDNA can re-nature to dsDNA. While it is easy for the the small circular plasmid DNA to re-nature, it is impossible to properly anneal the huge gDNA (chromosomal DNA) stretches.
However, vigorous mixing or vortexing will shear the gDNA producing shorter stretches that can re-anneal and contaminate your plasmid prep.
While the double-stranded plasmid can dissolve easily in solution, the single stranded genomic DNA, the SDS and the denatured cellular proteins stick together through hydrophobic interactions to form a white precipitate.
The precipitate can easily be separated from the plasmid DNA solution by centrifugation.
May it helps
Best regards
@Hasan Nasrullah it was really so kind of you to explain in depth. Thanks a lot for your time and efforts.
With best regards!
- Badges
- Science topic