Figure 1 - full size

Figure 1.
Figure 1. F6 displays higher processivity than does RB69 DNA polymerase. Primers were 5 end labeled ^32P 20-mers and are complementary to different regions on M13mp18. Proteins were incubated for 2 min at 30°C with annealed primer-template DNA and dNTPs. Reactions were initiated by the addition of MgCl[2] and stopped by the addition of EDTA/formamide loading buffer. Some of the reactions also have 500 g/mL heparin to produce single turn-over kinetics. Reaction products are separated on a 6% polyacrylamide-7M urea gel. Lane 1: Reaction mixture without enzyme. Lane 2: Heparin was added before F6 as a control to show that the fusion binds heparin and is an effective single-turnover sink. Lane 3-15: Reactions with different protein and protein combinations with/without heparin at different time points showing that compared with RB69 DNA polymerase, F6 has increased processivity. A. Reactions with P1 as primer. B. The primer P2 is complementary to a region on M13mp18, where there is a major replication pause site (12 bp hairpin structure) 105 nt downstream. As shown in Lane 3, F6 was able to overcome this major pause site and continue DNA synthesis, while all other protein and protein combinations stopped.