Figure 2.

Modification in vivo of plasmid GG^A/_TCC and GG^G/_CCC sites by the WT and mutant SinI MTase. Methylation status of the plasmids was tested by digestion with Eco47I (specificity GG^A/_TCC) or Cfr13I (GGNCC). Lane 1, pTZS (undigested); lane 2, pTZS–Eco47I; lane 3, pTZS–Cfr13I; lane 4, pTZSmut–Eco47I; lane 5, pTZSmut–Cfr13I; lane 6, pTZSmut45–Eco47I; lane 7, pTZSmut45–Cfr13I; lane 8, pTZSmut123–Eco47I; lane 9, pTZSmut123–Cfr13I; and lane 10, DNA size marker. All plasmids tested have two GG^A/_TCC sites. The 222 bp fragment generated by digestion at the GG^A/_TCC sites is indicated by asterisk. pTZS and pTZSmut123 carry nine GG^G/_CCC sites (six in the vector, three in the M.SinI gene), whereas pTZSmut and pTZSmut45 have an additional GG^G/_CCC site created by the mutagenesis process. Electrophoresis carried out in a 1.5% agarose gel.