Results 1 - 10
of
19
Single-Molecule Imaging of DNA Pairing by RecA Reveals a Three-Dimensional Homology Search. Nature 2012
"... DNA breaks can be repaired with high-fidelity by homologous recombination. A ubiquitous protein that is essential for this DNA template-directed repair is RecA1. After resection of broken DNA to produce single-stranded DNA (ssDNA), RecA assembles on this ssDNA into a filament with the unique capacit ..."
Abstract
-
Cited by 14 (0 self)
- Add to MetaCart
DNA breaks can be repaired with high-fidelity by homologous recombination. A ubiquitous protein that is essential for this DNA template-directed repair is RecA1. After resection of broken DNA to produce single-stranded DNA (ssDNA), RecA assembles on this ssDNA into a filament with the unique capacity to search and find DNA sequences in double-stranded DNA (dsDNA) that are homologous to the ssDNA. This homology search is vital to recombinational DNA repair, and results in homologous pairing and exchange of DNA strands. Homologous pairing involves DNA sequence-specific target location by the RecA-ssDNA complex. Despite decades of study, the mechanism of this enigmatic search process remains unknown. RecA is a DNA-dependent ATPase, but ATP hydrolysis is not required for DNA pairing and strand exchange2,3, eliminating active search processes. Using dual optical trapping to manipulate DNA, and single-molecule fluorescence microscopy to image DNA pairing, we demonstrate that both the three-dimensional conformational state of the dsDNA target and the length of the homologous RecA-ssDNA filament play important roles in the homology search. We discovered that as the end-to-end distance of the target dsDNA molecule is increased, constraining its available 3-dimensional
www.mdpi.com/journal/ijms Optical Methods to Study Protein-DNA Interactions in Vitro and in Living Cells at the Single-Molecule Level
, 2013
"... Abstract: The maintenance of intact genetic information, as well as the deployment of transcription for specific sets of genes, critically rely on a family of proteins interacting with DNA and recognizing specific sequences or features. The mechanisms by which these proteins search for target DNA ar ..."
Abstract
-
Cited by 2 (0 self)
- Add to MetaCart
(Show Context)
Abstract: The maintenance of intact genetic information, as well as the deployment of transcription for specific sets of genes, critically rely on a family of proteins interacting with DNA and recognizing specific sequences or features. The mechanisms by which these proteins search for target DNA are the subject of intense investigations employing a variety of methods in biology. A large interest in these processes stems from the faster-than-diffusion association rates, explained in current models by a combination of 3D and 1D diffusion. Here, we present a review of the single-molecule approaches at the forefront of the study of protein-DNA interaction dynamics and target search in vitro and in vivo. Flow stretch, optical and magnetic manipulation, single fluorophore detection and localization as well as combinations of different methods are described and the results obtained with these techniques are discussed in the framework of the current facilitated diffusion model. Int. J. Mol. Sci. 2013, 14 3962
Structural and torsional properties of the RAD51-dsDNA nucleoprotein filament
, 2013
"... Human RAD51 is a key protein in the repair of DNA by homologous recombination. Its assembly onto DNA, which induces changes in DNA structure, results in the formation of a nucleoprotein filament that forms the basis of strand exchange. Here, we determine the structural and mechanical properties of R ..."
Abstract
-
Cited by 2 (1 self)
- Add to MetaCart
(Show Context)
Human RAD51 is a key protein in the repair of DNA by homologous recombination. Its assembly onto DNA, which induces changes in DNA structure, results in the formation of a nucleoprotein filament that forms the basis of strand exchange. Here, we determine the structural and mechanical properties of RAD51-dsDNA filaments. Our measurements use two recently developed magnetic tweezers assays, freely orbiting magnetic tweezers and magnetic torque tweezers, designed to measure the twist and torque of individual molecules. By directly moni-toring changes in DNA twist on RAD51 binding, we determine the unwinding angle per RAD51 monomer to be 45, in quantitative agreement with that of its bacterial homolog, RecA. Measurements of the torque that is built up when RAD51-dsDNA filaments are twisted show that under conditions that suppress ATP hydrolysis the torsional persistence length of the RAD51-dsDNA filament exceeds that of its RecA counterpart by a factor of three. Examination of the filament’s torsional stiffness for different combinations of divalent ions and nucleo-tide cofactors reveals that the Ca2+ ion, apart from suppressing ATPase activity, plays a key role in increasing the torsional stiffness of the filament. These quantitative measurements of RAD51-imposed DNA distortions and accumulated mechan-ical stress suggest a finely tuned interplay between chemical and mechanical interactions within the RAD51 nucleoprotein filament.
unknown title
"... Force et couple dans les pinces magnétiques: Paysage énergétique de la protéine hRad51 sur ADN double-brin Soutenue le 26 Septembre 2014 devant le jury composé de: ..."
Abstract
- Add to MetaCart
(Show Context)
Force et couple dans les pinces magnétiques: Paysage énergétique de la protéine hRad51 sur ADN double-brin Soutenue le 26 Septembre 2014 devant le jury composé de:
unknown title
, 2009
"... Visualizing RAD51-mediated joint molecules: implications for recombination mechanism and the effect of sequence heterology ..."
Abstract
- Add to MetaCart
(Show Context)
Visualizing RAD51-mediated joint molecules: implications for recombination mechanism and the effect of sequence heterology
unknown title
, 2009
"... Visualizing RAD51-mediated joint molecules: implications for recombination mechanism and the effect of sequence heterology ..."
Abstract
- Add to MetaCart
(Show Context)
Visualizing RAD51-mediated joint molecules: implications for recombination mechanism and the effect of sequence heterology
unknown title
, 2009
"... Visualizing RAD51-mediated joint molecules: implications for recombination mechanism and the effect of sequence heterology ..."
Abstract
- Add to MetaCart
(Show Context)
Visualizing RAD51-mediated joint molecules: implications for recombination mechanism and the effect of sequence heterology
Insights into the mechanism of Rad51 recombinase
, 2010
"... from the structure and properties of a filament interface mutant ..."
(Show Context)
unknown title
, 2009
"... Leishmania actin binds and nicks kDNA as well as inhibits decatenation activity of type II topoisomerase ..."
Abstract
- Add to MetaCart
(Show Context)
Leishmania actin binds and nicks kDNA as well as inhibits decatenation activity of type II topoisomerase
Nucleic Acids, and Motor Proteins
"... This document contains the draft version of the following paper: ..."
(Show Context)
