Figure 3.

Vector pS189 derivatives containing two C/C mismatches. (A) Scheme illustrating the location of C/C^SfiI (position 3578) in the SV40 origin of pS189. The pentanucleotide recognition sequences for T antigen binding are indicated by the arrows. (B) Composition of substrates 1 and 2. (C) Restriction analysis of substrate 1 (lanes 4–6) and substrate 2 (lanes 9–11). The homoduplex vector was prepared by extension and ligation of unmodified primers. Control, no restriction endonuclease added.