1. Pick a single colony of host cell (e.g., XL1-blue MRF' for a ZAP II library
on LB-tetracycline plate).
2. Grow overnight in 50 ml of LB/0.2% maltose/10 mM MgSO4
at 30 °C.
3. Pellet cells. And resuspend cells in 10 ml of 10 mM MgSO4.
4. Dilute cells with 10 mM MgSO4 to
OD4 ~ 0.5.
5. Cells can be stored at 4 °C for less than 1 month.