Skip to main content
. Author manuscript; available in PMC: 2013 Nov 1.
Published in final edited form as: Trends Biochem Sci. 2012 Sep 2;37(11):499–506. doi: 10.1016/j.tibs.2012.08.002

Figure 2.

Figure 2

A revised model of the bacterial DNA polymerase based on stoichiometry data obtained using stepwise photobleaching. Three Pol III polymerase cores (orange) exist in each replisome, two of which are usually associated with β clamps, and the third might be poised to extend the next lagging strand primer. A third β clamp is distant to the core replisome (50 nm gray circle) in 75% of replisomes. Previous models included only two polymerases coordinately replicating the leading and lagging DNA strands. The presence of a third Pol III may help lagging strand synthesis keep pace with leading strand synthesis. From Reyes-Lamothe et al., Science, 2010. Reprinted with permission from AAAS.