Berglund:CaCl2 cells

Preparation of CaCl2 (heat-shock) competent cells

row 500ml-1L to an OD600 between 0.4 ad 0.6
Place cells on ice for 15 minutes
spin down cells 4000rcf for 10 minutes
resuspend gently in half the pellt volumes of ice cold 50mM CaCl2
Let sit on ice for 30 minutes
spin down cells 4000rcf for 10 minutes
resuspend the cells gently in 1/20 of the pellet volume in ice cold 50mM CaCl2 + 10% glycerol
incubate at least one hour on ice
make 300µl aliquots (use 100µl per transformation)
quice freeze in a dry ice/ethanol bath or liquid nitrogen
store at -80.

Transformation protocol
add 1µl (100ng) plasmid and heat shock for 45 seconds at 42 degrees in a water bath