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UID:0-984@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20241018T110000
DTEND;TZID=Europe/Paris:20241018T120000
DTSTAMP:20241014T203524Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i
 nterface-seminar-amelie-leforestier/
SUMMARY:Physics-Biology Interface seminar: Amélie Leforestier - Moyen Amph
 i\, Building 510\, Université Paris-Saclay Orsay - 18 Oct 24 11:00
DESCRIPTION:Electrostatic zipper in curved DNA condensates\nAmélie Lefores
 tier (U. Paris-Saclay)\nJoint seminar with LPS: beware of the unusual loca
 tion\nIn helical polyelectrolytes like DNA\, the electrostatic zipper is a
  model of interaction\, which\, taking into account the helical surface ch
 arge distribution\, predicts mutual azimuthal orientation of close-packed 
 molecules. This phenomenon is poorly documented experimentally. In particu
 lar\, electrostatic zipper is not compatible with curvature\, a general fe
 ature of dense states of DNA\, both in vitro and in vivo. Using cryo-EM im
 aging of DNA toroids\, we analyze the relationship between curvature\, hel
 ical correlations\, and DNA helical pitch. We show that in phase helical a
 lignments are preferred over a wide range of ionic concentrations. Optimiz
 ation of this preferred configuration is associated to rearrangements with
 in the toroid as it grows\, with establishment of the EZ followed by a glo
 bal polygonal shaping. In addition\, a local decrease in the DNA helical p
 itch is measured in highest curvature regions. This phenomenon\, at work i
 n DNA toroids\, is also likely to occur in spheroidal globules\, bacteriop
 hage chromosomes\, and\, more generally\, all forms of curved condensed DN
 A – and other helical polyelectrolytes – both in vivo and in vitro. In
  particular\, it should be taken into account in material design involving
  curved DNA origami.
CATEGORIES:physbio,seminars
LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R
 ue Georges Clemenceau\, orsay\, France
GEO:48.698187;2.181768
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 iversité Paris-Saclay Orsay:geo:48.698187,2.181768
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