snik-short

Short protocol for plasmid mini-prep, see long protocol here.

1. Transfer 1-2 mL of culture to a new Eppendorf tube.
2. Centrifuge at top speed for 30 s to recover cells in a pellet.
3. Remove supernatant with a pipette or by decanting. 
4. Add 200 µL of Buffer P1 to the pellet. Mix by pipetting up and down pipette or by vortexing briefly.
5. Add 200 µL buffer P2, mix by slowly inverting the tube during ~4 min.
6. Add 250 µL  buffer P3, mix by slowly inverting the tube at least ten times
7. Centrifuge at top speed for 10 min.
8. Transfer ~500 µL of the supernatant to 1 mL 100% ethanol in a fresh tube and mix by inversion.
9. Centrifuge at top speed for 10 min. Make sure the hinge of the tube is facing outwards. 
10. Pour away supernatant. The plasmid DNA should be visible as a white spot.
11. Add 1 mL 70% EtOH. Mix by inverting the tube 2-3 times. 
12. Centrifuge for 1 min at top speed. 
13. Pour away supernatant by opening and inverting the tube.
14. Evaporate ethanol by opening the lid of the tube and leave it on the bench for 15 min or at 50 °C for 5 min. 
15. Resuspend DNA pellet in 50 µL 1x TE buffer. 
16. Store the tube in fridge or freezer (4 °C or -20 °C)