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SUMMARY:Structural insights into the DDX11 helicase
DTSTART;VALUE=DATE-TIME:20260326T110000Z
DTEND;VALUE=DATE-TIME:20260326T113000Z
DTSTAMP;VALUE=DATE-TIME:20260426T030124Z
UID:indico-contribution-10324@events.saip.org.za
DESCRIPTION:Speakers: Silvia Onesti (N/A)\nHelicases are essential and ubi
 quitous enzymes\, playing a key role in a variety of processes in DNA and 
 RNA metabolism. A subset of helicases play specialised and specific functi
 ons by resolving/remodelling a variety of atypical DNA structures\, such a
 s G-quadruplexes\, triplexes\, Holliday junctions\, as well as displacemen
 t loops (D-loops and R-loops): among those a major role is played by the F
 eS family. Helicases containing FeS-clusters are ubiquitous but their exac
 t mechanism of action is poorly understood\; no structural information is 
 available for some medically-relevant members of the family\, like FANCJ\,
  DDX11 and RTEL1.The combination of the intrinsic conformational flexibili
 ty\, FeS cluster lability and size makes them challenging targets for stru
 ctural biology.\n\nDDX11 plays an important role in sister-chromatid cohes
 ion\, associates with the replisome and is involved in processing non-cano
 nical nucleic acid structures. We have expressed and purified the human pr
 otein with an intact FeS cluster and carried out an extensive biochemical 
 characterization. We have collected Cryo-EM data for the protein alone and
  in complex with a DNA fork: the apo structure is being refined at 3.5 Å 
 resolution and a preliminary 5 Å structure in complex with a DNA fork has
  been determined. We can clearly see the path of the DNA fork bound to the
  helicase including the double helix\, and the 5’ single strand across t
 he motor domains. Interestingly\, in same regions the structure differs si
 gnificantly from the AlphaFold model. \nThese structures provide an essent
 ial framework to better understand the role of these enzymes.\n\nhttps://e
 vents.saip.org.za/event/272/contributions/10324/
LOCATION:
URL:https://events.saip.org.za/event/272/contributions/10324/
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