Plasmid Precipitation using spermine

1, Spin down 2~5 ml E coli cells.
2. Add 0.25 ml P1.
3, Resuspend by votexing.
4, Add 0.25 ml P2. Lyse for 2~5 min.
5. Add 0.35 ml N3, mix
6. Spin for 2~5 min.
7. Transfer supernatant to another clean 1.5 ml microcentrifuge tube.
8. Add 0.7 vol of isopropanol (0.6 ml).
9. Spin for 3~5 min, dump off liquid.
10. Resuspend pellet in 100 ul of EB (10 mM Tris HCl, pH 8.0)
11. Add 100 ul of 2.9 mM spermidine stock. Vortex
12. Spin for 1~2 min.
13. Wash with 300 ul of 50% isopropanol solution of 10 mM MgCl2, 300 mM NaCl, and 25 mM EDTA.
14. Wash with 100 ul of 70% ethanol.
15. Remove residual ethanol
16. Dissolve pellet in 50 ul EB.

Large Scale Purification

After precipitation, DNA is dissolved in EB and load to a Q Sepharose high-performance Spectrum column (2.5 cm x 60 cm) packed with 150 ml Q Sepharose high-performance and equilibrated in 10 column volumes of TE with 570 mM NaCl. Loading and elution is performed at a linear velocity of 90 cm/hr.