Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 12: Single Molecules
BP 12.8: Vortrag
Mittwoch, 25. März 2009, 12:00–12:15, HÜL 186
Stretching and unfolding titin: Metastability and survival of the fittest — •Douglas B. Staple1,2, Stephen H. Payne1, Andrew L. C. Reddin1, and Hans Jürgen Kreuzer1 — 1Dalhousie University, Halifax, Canada — 2Max-Planck-Institut für Physik komplexer Systeme, Dresden, Germany
Single-molecule manipulation has allowed the forced unfolding of multidomain proteins. Here we outline a theory that not only explains these experiments but also points out a number of difficulties in their interpretation and makes suggestions for further experiments. For titin we reproduce force-extension curves, the dependence of break-force on pulling speed, and break-force distributions and also validate two common experimental views: unfolding titin Ig domains can be explained as stepwise increases in contour length, and increasing force peaks in native Ig sequences represent a hierarchy of bond strengths. Our theory is valid for essentially any molecule that can be unfolded in atomic force microscopy; as a further example, we present force-extension curves for the unfolding of RNA hairpins.