I am having difficulty with purifying plasmids from ABLE-K cells. I have had no problems using qiagen mini prep kits in the past for other e. coli strains. It is my understanding that ABLE-K cells decrease plasmid copy number by 10-fold. Not surprisingly mini prep w/ 1.5ml of culture volume did not produce a plasmid on gel electrophoresis. Retried this using 10ml spun down and reconstituted in 2ml, still no plasmid. Tried a solution based mini prep method, but had a smear on gel electrophoresis (likely genomic DNA contamination); however, no sign of plasmid.

Has anyone else used ABLE-K cells, and what was your protocol to purify plasmids for diagnostic digestion?