DNA Replication                                                               >>Back to Notes>> DNA DNA polymerase III (Pol III) enzyme forms a protein ring around the DNA, as it attaches new dNTPs to the 3' OH end of the growing chain of the leading strand, which elongates in the direction  5' to 3' toward the replicating fork.  (For each origin, there are TWO leading strands; why?)  For each NTP, a pyrophosphate (PP) is released, providing the necessary energy.