Transformation of competent E.coli cells with plasmid DNA
Thaw the appropriate amount of competent cells on ice.
Pre-chill the required number of empty 1.5 ml microcentrifuge tubes.
Pipet 100 µl aliquots of cells into the pre-chilled tubes.
Add 5-10 µl of a ligation reaction mix or 5 ng of pure plasmid DNA to each tube.
Mix gently!
Incubate the tubes of ice for 30 min. 
Heat shock the cells for 45 sec at 42°C. 
Place the tubes immediately on ice for at least 2 min. 
Add 1000 µl of SOC medium to each tube and incubate for 1 hour at 37°C with shaking.
Transfer the cultures to 1.5 ml microcentrifuge tubes and spin for 1 min at 10000 x g. 
Remove 800 µl of the supernatant and resuspend the pellet.
Plate out the suspension on a LB agar plate containing the appropriate antibiotic.
Incubate the plates overnight at 37°C.
