DNA/protein interactions at the single molecule level.

David Bensimon

Laboratoire de Physique Statistique de l'Ecole Normale Sup\'{e}rieure

24, rue Lhomond -- 75231 Paris Cedex 05, France

The possibility to manipulate a single DNA molecule has opened a new vista on the study of its interactions with structural and regulating proteins. We shall review the existing techniques to stretch and twist single DNA molecules and will compare this methodology with the well known patch-clamp technique that has allowed the study of single channels for the past 20 years. The possibility to observe individual molecules allows for a better characterization of their enzymatic cycle as the thermodynamic parameters and their distribution are thus made available.

We shall see how this program can be implemented in a few examples: DNA-polymerases, helicases and topoisomerases.