Bacterial DNA polymerase III
is part of a


[a protein complex including
helicase, primase at replication fork]

  that replicate both
      strands simultaneously

catalytic subunit   =  α              
proofreading subunit  =  ε

the blue/yellow dimers
make clamps that encircle
DNA template and move
DNA through the
catalytic unit (
α  ) like
a string through a ring.