Unformatted text preview: e multi-protein complex that acts as
in bacteria the main workhorse of replication. • It has two activities: • 5’-to-3’ polymerase activity allows it to add new nucleotides • 3’-to-5’ exonuclease activity allows it to remove nucleotides
to correct errors 3. Elongation: DNA polymerases • DNA polymerase III: • once you bind, it continues over and over again High processivity - capable of adding many nucleotides to
the growing DNA strand without releasing the template • Beta subunit serves as a clamp for the polymerase enzyme,
encircling the DNA - this increases processivity 3. Elongation: DNA polymerases • DNA polymerase I • Similarly has: • 5’-to-3’ polymerase activity • 3’-to-5’ exonuclease activity 3. Elongation: DNA polymerases • DNA polymerase I • Also has 5’-to-3’ exonuclease activity • Used to remove RNA primers laid down by primase and
then replace them with DNA • Lower processivity. The removal and replacement of primers
appears to constitute the main function of DNA polymerase I.
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