000 02497 am a22002773u 4500
042 _adc
100 1 0 _aTapia-Rojo, Rafael
_eauthor
_92343
700 1 0 _aMora, Marc
_eauthor
_92344
700 1 0 _aBoard, Stephanie
_eauthor
_92345
700 1 0 _aWalker, Jane
_eauthor
_92346
700 1 0 _aBoujemaa-Paterski, Rajaa
_eauthor
_92347
700 1 0 _aMedalia, Ohad
_eauthor
_92348
700 1 0 _aGarcia-Manyes, Sergi
_eauthor
_92349
245 0 0 _aEnhanced statistical sampling reveals microscopic complexity in the talin mechanosensor folding energy landscape
260 _c2023-01.
500 _a/pmc/articles/PMC7614079/
500 _a/pubmed/36660164
520 _aStatistical 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.
540 _a
540 _ahttps://creativecommons.org/licenses/by/4.0/This work is licensed under a CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) International license.
546 _aen
690 _aArticle
655 7 _aText
_2local
786 0 _nNat Phys
856 4 1 _uhttp://dx.doi.org/10.1038/s41567-022-01808-4
_zConnect to this object online.
999 _c2250
_d2250