Eur. Phys. J. E (2006) 19: 311-317
https://doi.org/10.1140/epje/i2005-10060-4

Focus Point

Probing DNA and RNA single molecules with a double optical tweezer

¹ Laboratoire de Nanobiophysique, UMR CNRS 7083, ESPCI, 10 rue Vauquelin, 75231, Paris Cedex 05, France
² Laboratoire Pierre Aigrain, Ecole Normale Supérieure, 24 rue Lhomond, 75231, Paris Cedex 05, France
³ Institut de Biologie Physico-chimique, UPR CNRS 9073, 13 rue Pierre et Marie Curie, 75005, Paris, France

^* e-mail: ulrich.bockelmann@espci.fr

Received: 7 September 2005
Accepted: 16 January 2006
Published online: 17 February 2006

Abstract

A double-tweezer setup is used to induce mechanical stress in systems of molecular biology. A double strand of DNA is first stretched and the data is compared to precedent experiments to check the experimental setup. Then a short foldable fragment of RNA is probed; the typical unfolding/refolding hysteresis behaviour of this kind of construction is shown and followed by a study of its elasticity and a comparison to a worm-like chain model. Eventually, we describe the unfolding of a larger RNA structure, which unfolds by multiple steps. We show that this unfolding is not reversible and that it presents numerous unfolding pathways.