1 / 21

Mechanism of DNA Translocation in Replicative Helicase

Explore the intricate process of DNA replication and translocation, with emphasis on the function and structure of helicase enzymes in unwinding and facilitating DNA repair and recombination. Crystal structures and models provide insights into helicase mechanisms and crystalization conditions.

stephenmccormick
Download Presentation

Mechanism of DNA Translocation in Replicative Helicase

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related