Pol III* can exchange into the replication fork.
A, protein components required for a rolling circle reaction were added to a premixed solution of wild-type Pol III* and D403E Pol III*. After initiation complex formation, the rolling circle replication reaction was started by addition of 1 mm ATP, 100 μm dNTPs, and α-[32P]dCTP or α-[32P]dGTP. B, D403E Pol III* was added at the designated final concentration to an ongoing rolling circle reaction.