Figure 9.

DNA melting and annealing by ORF1p and M128p. These experiments were carried out as described in the ‘Materials and Methods’ section. The indicated amounts of protein (in terms of monomer) were incubated with the appropriate substrates for 5 min at 37°C, whereupon the fractions of single-stranded or double-stranded DNA were determined by gel electrophoresis as described for the experiments in Figure 8. (A) The ORF1p data are taken from the lower plot of Figure 8B (open squares in both cases). The mismatched duplex DNA (1 nM) used for M128p was (d29:[³²P]-d29_cmm). The differences in the ultimate fraction of single-stranded DNA produced reflect the different values for the fraction of single-stranded DNA generated at 37°C in the absence of protein, which were subtracted from these values (see text). (B) Annealing assays with 2 nM d29 and 1.8 nM [³²P]-d29_c (filled circles) or 1.8 nM [³²P]-d29 and 2 nM d29_c (the other symbols). All of the results in (A) and (B) were generated in independent reactions.