Figure 2

The molecular models, rendered to scale, of a DNA replication fork. Structures of four of ten T4 proteins are known; the RNase H (tan), the gp59 helicase loading protein (rose), the gp45 clamp (magenta), and the gp32 ssb (orange). Two additional structures from RB69, a T4 related phage, have also been completed; the RB69 gp43 polymerase (light blue) and the gp45 clamp (not shown). The E. coli clamp loader (γ complex) (pink) is used here in place of the T4 gp44/62 clamp loader, and two proteins from bacteriophage T7, T7 ligase (green) and T7 gene 4 helicase-primase (blue/salmon) are used instead of T4 ligase, and gp41/gp61, respectively.