Prokaryote Replication

Prokaryote Replication - Prokaryote Replication: Initation...

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Prokaryote Replication: Initation 1. DnaA-ATP (activated) binds to origin = DUE unwinds DUE (DnaA-dependent denaturation of the DUE region) 2. DnaC-dependent loading of DnaB helicase 3. DnaB (helicase) two of them, go bidirectionally opening the two DNA strands. Elongation: Priming 1. primase • An enzyme that catalyzes the formation of RNA oligonucleotides used as primers by DNA polymerases. (polymerization) 2. DNA polymerase III synthesize (only 5’ 3’) 3. yay leading strands…now what? a. Leading strand synthesis is continuous (in direction of fork movement) b. Lagging strand synthesis is discontinuous (opposite to fork movement) Elongation Lagging Strand Synthesis 1. DnaB (helicase) opens the DNA (5’-3’) 2. DNA topoisomerase II (DNA gyrase) twists opposite DnaB helicase to reduce strain 3. Continuous strand goes on happily 4. Primase writes an RNA primer and once the DNA is open enough, it dissociates and is replaced by DNA Polymerase III (2 cores, 3 B-clamps) a. Single Strand Binding Proteins ( SSB) to keep the single strand DNA from folding up on itself 5. Second DNA Polymerase III core starts writing the lagging strands starting at the RNA primer 6. Second DNA Polymerase III core keeps up its pattern with the primase adding new RNA primers Lots of Okazaki fragments UNTIL THE END Elongation: Removal of RNA primers 1. There is a Nick between the end of the last Okazaki fragment and the beginning
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Prokaryote Replication - Prokaryote Replication: Initation...

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