Regensburg 2016 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 12: Single Molecule Biophysics

BP 12.3: Vortrag

Montag, 7. März 2016, 15:45–16:00, H45

Single-molecule protein nanomechanics of the chaperone DnaK — •Gabriel Zoldak and Matthias Rief — Physik-Department E22, Technische Universität München James-Franck-Str. 1 85748 Garching Germany

In the last few years, single molecule force spectroscopy has become recognized as an excellent and unique method for probing energy landscapes of large conformational changes in proteins, including protein folding and ligand binding. Conceptually, the force spectroscopy can be applied as a tool for: (1) monitoring single-molecule kinetics with exceptional resolution, and (2) characterizing local mechanics. In the first study, we expand the dynamic range of single-molecule force spectroscopy using optical tweezers by autocorrelation analysis which pushes the time resolution of single-molecule force spectroscopy to ca. 10 microseconds thus approaching the timescales accessible for all-atom molecular dynamics simulations. In the second study, we elucidate the energetic and mechanical changes within the subdomains of the nucleotide binding domain (NBD) of the heat shock protein of 70 kDa (Hsp70) chaperone DnaK upon nucleotide binding. In an integrated approach using single molecule optical tweezer experiments, loop insertions, and steered coarse-grained molecular simulations, we find that the C-terminal helix of the NBD is the major determinant of mechanical stability, acting as glue between the two lobes. After helix unraveling, the relative stability of the two separated lobes is regulated by ATP/ADP binding.