Enhanced statistical sampling reveals microscopic complexity in the talin mechanosensor folding energy landscape.

Autor: Tapia-Rojo R; Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK.; Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King's College London, Strand, WC2R 2LS London, United Kingdom., Mora M; Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK.; Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King's College London, Strand, WC2R 2LS London, United Kingdom., Board S; Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK.; Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King's College London, Strand, WC2R 2LS London, United Kingdom., Walker J; Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK.; Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King's College London, Strand, WC2R 2LS London, United Kingdom., Boujemaa-Paterski R; Department of Biochemistry, Zurich University, Winterhurerstrasse 190, CH-8057, Zurich, Switzerland., Medalia O; Department of Biochemistry, Zurich University, Winterhurerstrasse 190, CH-8057, Zurich, Switzerland., Garcia-Manyes S; Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK.; Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King's College London, Strand, WC2R 2LS London, United Kingdom.
Jazyk: angličtina
Zdroj: Nature physics [Nat Phys] 2023 Jan; Vol. 19 (1), pp. 52-60. Date of Electronic Publication: 2022 Nov 07.
DOI: 10.1038/s41567-022-01808-4
Abstrakt: Statistical mechanics can describe the major conformational ensembles determining the equilibrium free-energy landscape of a folding protein. The challenge is to capture the full repertoire of low-occurrence conformations separated by high kinetic barriers that define complex landscapes. Computationally, enhanced sampling methods accelerate the exploration of molecular rare events. However, accessing the entire protein's conformational space in equilibrium experiments requires technological developments to enable extended observation times. We developed single-molecule magnetic tweezers to capture over a million individual transitions as a single talin protein unfolds and refolds under force in equilibrium. When observed at classically-probed timescales, talin folds in an apparently uncomplicated two-state manner. As the sampling time extends from minutes to days, the underlying energy landscape exhibits gradually larger signatures of complexity, involving a finite number of well-defined rare conformations. A fluctuation analysis allows us to propose plausible structures of each low-probability conformational state. The physiological relevance of each distinct conformation can be connected to the binding of the cytoskeletal protein vinculin, suggesting an extra layer of complexity in talin-mediated mechanotransduction. More generally, our experiments directly test the fundamental notion that equilibrium dynamics depend on the observation timescale.
Competing Interests: Competing interests The authors declare no competing interests.
Databáze: MEDLINE
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