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La recombinaison homologue sur molécule unique d'ADN: mesures de torsion et de couple.

Abstract : In this thesis, we have studied the mechanics and thermodynamics of a crucial process for repairing DNA breaks: homologous recombination. Some preleminary experiments on the observation of stretched DNA during homologous recombination have shed light on the complexity of this process and the difficulty to observe it in fluorescence. We have then developed a new technique called "torque sensitive magnetic tweezers" which allows us to hold a single DNA molecule with a known force and torque and in the meantime to measure its torsion with a resolution of a few degrees. Thus we have shown in a direct manner that the polymerization of the recombinase hRad51 occurs by the adding of monomers, each one unwinding the DNA by 65° in mean. We have also been able to measure the torque which stalls the polymerization. A mechano-chemical modelling has eventually allowed us to estimate the chemical potential of the polymerization which is in good agreement with the existing biochemical data.
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Submitted on : Thursday, December 11, 2008 - 1:35:46 PM
Last modification on : Tuesday, December 7, 2021 - 10:58:03 AM
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  • HAL Id : tel-00346315, version 1


Aurélie Dupont. La recombinaison homologue sur molécule unique d'ADN: mesures de torsion et de couple.. Biophysique []. Université Paris-Diderot - Paris VII, 2008. Français. ⟨tel-00346315⟩



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