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Mécanismes de diffusion facilitée de l'enzyme de restriction EcoRV.

Abstract : Some proteins can rapidly locate a short recognition site within large DNA using "facilitated diffusion", a process in which protein first bind to the DNA via non-specific interactions and then translocate along DNA to the specific sequence. "Sliding" (1D diffusion) and "jumping" (3D translocations) on DNA are two mechanisms that are believed to accelerate target location, but their respective roles in facilitated diffusion remains to be clarified.
Using total internal fluorescence microscopy, we studied the "facilitated diffusion" of the restriction endonuclease EcoRV along stretched DNA on the single molecule level. In addition to sliding, we observed jumps which were demonstrated to stem from 3D excursions of the enzyme between distant DNA sites. We developed an analytical model based on 3D diffusion to account for both the jump frequency and the jump length distribution. We deduced from our study key parameters regarding the facilitated diffusion of EcoRV, such as the 1D diffusion coefficient (D1 ~ 0.01 µm2.s-1) and the number of jumps (~ 20) occurring during an interaction event with non-specific DNA.
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https://tel.archives-ouvertes.fr/tel-00197580
Contributor : Isabelle Bonnet <>
Submitted on : Friday, December 14, 2007 - 11:06:50 PM
Last modification on : Thursday, December 10, 2020 - 12:38:41 PM
Long-term archiving on: : Monday, April 12, 2010 - 8:03:01 AM

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  • HAL Id : tel-00197580, version 1

Citation

Isabelle Bonnet. Mécanismes de diffusion facilitée de l'enzyme de restriction EcoRV.. Biophysique [physics.bio-ph]. Université Pierre et Marie Curie - Paris VI, 2007. Français. ⟨tel-00197580⟩

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