FIG. 1.

DpnI and DpnII cleavage patterns of gDNA isolated from the E. coli GM33 (dam-deficient) strain containing pBAD plasmid with the native or mutated dam gene. (A) Lane 1, lambda DNA/HindIII markers (Promega); lanes 2, 3, and 4, gDNA from the E. coli GM33 strain (without any plasmid as a control) either without any restriction enzyme digestion (w/o R. E.) (lane 2) or treated with DpnI (lane 3) or DpnII (lane 4); lanes 5, 6, and 7, gDNA from E. coli GM33 containing the pBAD plasmid alone either with no enzyme digestion (w/o R. E.) (lane 5) or treated with DpnI (lane 6) or DpnII (lane 7); lanes 8 and 9, gDNA from E. coli GM33 containing the pBAD/dam_AhSSU recombinant plasmid treated with DpnI or DpnII enzymes; lanes 10 and 11, gDNA from the E. coli GM33 strain with the pBAD/dam_D/A plasmid treated with DpnI or DpnII; lanes 12 and 13, gDNA from E. coli GM33 strain carrying the pBAD/dam_Y/A plasmid treated with DpnI and DpnII, respectively; and lane 14, 1-kb DNA ladder (New England BioLabs). (B) Lanes 1 and 10, lambda DNA/HindIII markers (Promega) and 1-kb DNA ladder (New England BioLabs), respectively; lanes 2 and 3, gDNA from E. coli GM33 containing the pBAD/dam_AhSSU recombinant plasmid treated with DpnI or DpnII enzymes; lanes 4 and 5, gDNA from the E. coli GM33 strain with the pBAD/dam_D71A plasmid treated with DpnI or DpnII; lanes 6 and 7, gDNA from the E. coli GM33 strain carrying the pBAD/dam_E76A plasmid treated with DpnI and DpnII, respectively; lanes 8 and 9, gDNA from the E. coli GM33 strain with the pBAD/dam_D/A plasmid treated with DpnI or DpnII. All cultures which were used for the isolation of gDNA were grown in the presence of arabinose. The gDNA was digested at 37°C for 1 h and subjected to 1% agarose gel electrophoresis. The gels were visualized under UV light after being stained with ethidium bromide.