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DNA Replication

DNA Replication. Mechanism of DNA translocation in a replicative helicase. http://library.tedankara.k12.tr/chemistry/vol1/biochem/trans98.jpg. Helicase Function. Unwind dsDNA to make ssDNA DNA replication Repair Recombination.

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DNA Replication

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  1. DNA Replication Mechanism of DNA translocation in a replicative helicase http://library.tedankara.k12.tr/chemistry/vol1/biochem/trans98.jpg

  2. Helicase Function • Unwind dsDNA to make ssDNA • DNA replication • Repair • Recombination http://library.tedankara.k12.tr/chemistry/vol1/biochem/trans98.jpg

  3. Helicase Function • E1 & TAG (virus) • Recognize & melts origin to create ssDNA • Assemble on ssDNA • E1 3’-5’ to Unwind http://library.tedankara.k12.tr/chemistry/vol1/biochem/trans98.jpg

  4. Crystal structure of hexameric helicase (E1 of bovine papilomavirus) • Shows the path of DNA • Indicates mechanism

  5. Crystalization Conditions • Fragment BPV-1 E1 • Lacks N-term (306-577) • GST fusion • Concentrated with • 5 mM ADP • 200 mM MgCl2 • Oligo T (13 mer) • Mother liquor 100 mM KCl • Crystals • Flash frozen (N2 (lq)) • Synchotron Radiation • Molecular replacement http://en.wikipedia.org/wiki/Image:X_ray_diffraction.png

  6. 5’ 3’

  7. Courtesy of Chayne Piscitelli

  8. Loops roll

  9. D504, R505 & K508

  10. Staircase Model • A helicase staircase.Raney KD. Nat Struct Mol Biol. 2006 Aug;13(8):671-2.

  11. ATP?

  12. ADP Y534 ATP

  13. Escort Model

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