Dresden 2011 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 15: Single-Molecule Biophysics I

BP 15.1: Hauptvortrag

Dienstag, 15. März 2011, 10:15–10:45, ZEU 250

Single-molecule mechanics: theory, analysis, interpretation — •Olga Dudko — UC San Diego, La Jolla, California, USA

Single-molecule biophysical tools permit measurements of the mechanical response of individual biomolecules to external load, revealing details that are typically lost when studied by ensemble methods. An analytical theory of single-molecule force experiments will be presented. The proposed theoretical procedure, based on a picture of diffusive crossing of a free energy barrier, provides estimates of the intrinsic rate coefficient, the location of the transition state, and the free energy of activation. A quantitative, model-free relation between the data collected in two types of measurements - under constant force and under constant force ramp speed - is established. The theoretical procedure of analyzing and interpreting experimental data will be illustrated with the unzipping of individual nucleic acid-based structures by nanopores and optical tweezers and with the unfolding of individual proteins by an atomic force microscope. Effects of multidimensionality of the free energy landscape of the biomolecule on the nature of its response to force will be explored. The theory is applicable to biological contexts ranging from protein folding to ligand-receptor interactions.