FIGURE 4.

Effect of gp2.5 on DNA synthesis catalyzed by gp5/trx on ssDNA templates. The ability of wild-type (wt) gp5/trx and gp5/trx with alterations in loops A and B of the TBD to stimulate polymerase activity on ssDNA templates was examined as described under “Experimental Procedures.” The reactions (10 μl) contained M13 ssDNA annealed to 24-mer oligonucleotide (see inset) at a concentration of 10 nm; 0.5 mm each of dATP, [³H] dTTP, dGTP, and dCTP; and 1 and 0 nm of the indicated gp5/trx in the presence and absence of 4 μm gp2.5. After incubation at 37 °C for 3 min, the amount of DNA synthesis was determined by the amount of [³H]dTMP incorporated into DNA.