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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-2676
DTSTART:20120629T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260420T041033Z
LAST-MODIFIED:20120619T191027Z
LOCATION:5310 Chamberlin
SUMMARY:Direct Observation of Base-Pair Stepping and Conformational Dy
 namics in Molecular Nanomachines\, R. G. Herb Condensed Matter Seminar
 \, Yann Chemla\, University of Illinois
DESCRIPTION:Optical traps or "tweezers"\, which utilize focused light 
 to trap and manipulate microscopic objects\, have emerged as a powerfu
 l tool in molecular biology\, biochemistry and biophysics.  My group u
 ses this technique to tackle a variety of biological questions\, in pa
 rticular how proteins involved in genome processing interact and move 
 along DNA.  In this talk\, I will focus on recent work on helicases\, 
 the molecular machines that catalyze the separation of the two strands
  of DNA. Specifically\, I will discuss new results on two helicases in
 volved in DNA repair\, Xeroderma pigmentosum group D protein (XPD) and
  <i>E. coli</i> UvrD helicase.<br>
\n<br>
\nUsing single-molecule assa
 ys developed in my lab combining microfluidics\, high-resolution optic
 al tweezers\, and simultaneous fluorescence microscopy\, we obtain an 
 unprecedented detailed view of helicase motor dynamics at the sub-nano
 meter scale.  These techniques allow us to record single base pair-sca
 le helicase activity simultaneously with stoichiometry and conformatio
 n\, and help us decipher the mechanism by which helicases unwind DNA. 
 Our data reveal how these nanomachines sense the DNA sequence they mus
 t unwind and how their conformational state modulates their activity. 
 I will discuss the biological implications of our findings.<br>
\n
URL:https://www.physics.wisc.edu/events/?id=2676
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