FAQ: Does plasmid size affect transformation efficiency (C3019)?
Yes. We transformed a series of plasmids ranging in size from 2.7 kb (pUC19) to 24 kb into NEB 5-alpha competent E.coli (NEB #C2987H) and NEB 10-beta competent E.coli (NEB #C3019H) side by side. We noted that the transformation efficiency was affected by the plasmid size. NEB 10-beta chemically competent cells are more efficiently transformed with large plasmids than NEB 5-alpha cells (see Figure on the NEB #C3019H product page). NEB 10-beta competent E.coli are recommended for the transformation of large plasmids and large assembly products generated by NEBuilder® HiFi, Gibson Assembly®, and Golden Gate Assembly reactions.