FIGURE 6.

Stimulation of the DNA polymerase activity of Pol γ and template DNA organization by E. coli SSB. A and B, a DNA polymerase assay was performed as described under “Experimental Procedures,” as in Fig. 3A except that EcSSB was used (diamonds). Dashed curves, DmmtSSB control. C, electron microscopy of E. coli SSB protein on M13 DNA. The binding reaction was performed at 30 mm KCl and 4 mm MgCl₂. The images are representative of template species formed at the following ratios of SSB tetramers/100 nucleotides, which correspond to the indicated individual phases of the stimulation of HsPol γ activity: initial stimulation, 0.85 and 1.3; maximal stimulation, 2.6; plateau, 5.1 (also see Table 1). Error bars, S.D.