To minimize self-ligated vector in your transformation, treat your linearized vector with a phosphatase to remove the 5′ phosphates necessary for ligation. This should improve the percentage of colonies with inserts.
Materials
- Linear DNA from restriction digest (heat-inactivation of restriction enzymes is necessary but DNA purification is not).
- Antarctic Phosphatase
- 10X Antarctic Phosphatase buffer
Procedure
- Add Antarctic Phosphatase buffer to a final concentration of 1X to linearized vector sample.
- Add 1μL Antarctic Phosphatase (probably should make final glycerol concentration less that 5%?)
- Incubate 60 mins at 37°C.
This should be sufficient to remove 5′ phosphates even from 5′ recessed ends like those produced by Pst I. - Heat-inactivate for 5 mins at 65°C.
- Proceed directly to ligation step.
Notes
NEB’s Antarctic Phosphatase