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Accueil du site > Séminaires > Séminaires 2007 > Mechanical manipulation of nucleic acids at 1kT energy resolution using optical tweezers

mardi 30 Octobre 2007 à 14 h

Mechanical manipulation of nucleic acids at 1kT energy resolution using optical tweezers

Felix RITORT

par Didier Poilblanc - 30 octobre 2007

Optical tweezers use the optical gradient force generated by a focused beam of light acting on an object with index of refraction higher than that of the surrounding medium to impart sub-piconewton forces. The possibility to detect such tiny forces together with the ability of measuring extensions with sub-nanometer resolution allows to characterize the thermodynamics and kinetics of individual molecules (e.g. nucleic acids and proteins) within 1kcal/mol (or, equivalently, 1kBT) energy resolution.

In this talk I will present a brief overview of the optical tweezers instrument we have recently incorporated in our laboratory (BIOSMALL lab) in the Faculty of Physics at the University of Barcelona. I will show the first results we have recently obtained on the mechanically unfolding of DNA structures. First I will present preliminary results on the mechanical unzipping (two strands separation) of long DNA molecules. These results show mechanical force as a promising tool to extract the values for the free energies of formation of complementary base pairs in nucleic acids. Finally, I will show experimental results in the study of dynamic force spectroscopy and kinetics of short DNA hairpins.