This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Fulconis, R. Articles by Viovy, J.-L. Search for Related Content PubMed PubMed Citation Articles by Fulconis, R. Articles by Viovy, J.-L.

Twisting and Untwisting a Single DNA Molecule Covered by RecA Protein

Renaud Fulconis ^*, Aurélien Bancaud ^*, Jean-Francois Allemand , Vincent Croquette , Marie Dutreix  and Jean-Louis Viovy ^*

^* Laboratoire Physico-Chimie Curie, UMR CNRS 168, Institut Curie, Paris, France; Laboratoire de Physique Statistique, UMR CNRS 8550, Ecole Normale Supérieure, Paris, France; and Laboratoire Génotoxicologie et Cycle Cellulaire, UMR CNRS 2027, Institut Curie, Orsay, France

Correspondence: Address reprint requests to Jean-Louis Viovy, Tel.: 33-1-42-34-67-52; Fax: 33-1-40-51-06-36; E-mail: jean-louis.viovy{at}curie.fr.

We study dsDNA-RecA interactions by exerting forces in the pN range on single DNA molecules while the interstrand topological state is controlled owing to a magnetic tweezers setup. We show that unwinding a duplex DNA molecule induces RecA polymerization even at moderate force. Once initial polymerization has nucleated, the extent of RecA coverage still depends on the degree of supercoiling: exerting a positive or negative torsional constraint on the fiber forces partial depolymerization, with a strikingly greater stability when ATPS is used as a cofactor instead of ATP. This nucleofilament's sensitivity to topology might be a way for the bacterial cell to limit consumption of precious RecA monomers when DNA damage is addressed through homologous recombination repair.

This article has been cited by other articles:

				J. Mine, L. Disseau, M. Takahashi, G. Cappello, M. Dutreix, and J.-L. Viovy Real-time measurements of the nucleation, growth and dissociation of single Rad51 DNA nucleoprotein filaments Nucleic Acids Res., December 18, 2007; 35(21): 7171 - 7187. [Abstract] [Full Text] [PDF]

				R. Fulconis, M. Dutreix, and J.-L. Viovy Numerical Investigation of Sequence Dependence in Homologous Recognition: Evidence for Homology Traps Biophys. J., June 1, 2005; 88(6): 3770 - 3779. [Abstract] [Full Text] [PDF]

				T. van der Heijden, J. van Noort, H. van Leest, R. Kanaar, C. Wyman, N. Dekker, and C. Dekker Torque-limited RecA polymerization on dsDNA Nucleic Acids Res., April 11, 2005; 33(7): 2099 - 2105. [Abstract] [Full Text] [PDF]