Editing Processivity (section)

==DNA binding interactions==
Polymerases interact with the [[phosphate]] backbone and the minor groove of the DNA, so their interactions do not depend on the specific nucleotide sequence.<ref name=morales>{{cite journal|last1=Morales|first1=Juan C|last2=Kool|first2=Eric T|title=Minor Groove Interactions between Polymerase and DNA: More Essential to Replication than Watson-Crick Hydrogen Bonds?|journal=J Am Chem Soc|date=1999|volume=121|issue=10|pages=2323–2324|doi=10.1021/ja983502+|pmid=20852718|pmc=2939743}}</ref> The binding is largely mediated by [[electrostatic]] interactions between the DNA and the "thumb" and "palm" domains of the metaphorically hand-shaped DNA polymerase molecule. When the polymerase advances along the DNA sequence after adding a nucleotide, the interactions with the minor groove dissociate but those with the phosphate backbone remain more stable, allowing rapid re-binding to the minor groove at the next nucleotide.

Interactions with the DNA are also facilitated by [[DNA clamp]] proteins, which are multimeric proteins that completely encircle the DNA, with which they associate at [[replication fork]]s. Their central pore is sufficiently large to admit the DNA strands and some surrounding water molecules, which allows the clamp to slide along the DNA without dissociating from it and without loosening the [[protein–protein interaction]]s that maintain the toroid shape. When associated with a DNA clamp, DNA polymerase is dramatically more processive; without the clamp most polymerases have a processivity of only about 100 nucleotides.  The interactions between the polymerase and the clamp are more persistent than those between the polymerase and the DNA. Thus, when the polymerase dissociates from the DNA, it is still bound to the clamp and can rapidly reassociate with the DNA.  An example of such a DNA clamp is PCNA (proliferating cell nuclear antigen) found in ''S. cervesiae''.