TY - JOUR
T1 - Enhanced statistical sampling reveals microscopic complexity in the talin mechanosensor folding energy landscape
AU - Tapia-Rojo, Rafael
AU - Mora, Marc
AU - Board, Stephanie
AU - Walker, Jane
AU - Boujemaa-Paterski, Rajaa
AU - Medalia, Ohad
AU - Garcia-Manyes, Sergi
N1 - Funding Information:
This work was supported in part by the Francis Crick Institute that receives its core funding from Cancer Research UK (FC001002), the UK Medical Research Council (FC001002) and the Wellcome Trust (FC001002). R.T.-R. is the recipient of a King’s Prize Fellowship. O.M. was funded by the Swiss National Foundation grant (310030_207453). This work was supported by the European Commission (Mechanocontrol, grant agreement 731957BBSRC), BBSRC sLoLa (BB/V003518/1), Leverhulme Trust Research Leadership Award (RL-2016-015), Wellcome Trust Investigator Award (212218/Z/18/Z) and Royal Society Wolfson Fellowship (RSWF/R3/183006), to S.G.-M.
Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2022/11/7
Y1 - 2022/11/7
N2 - 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 used 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. 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.
AB - 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 used 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. 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.
UR - http://www.scopus.com/inward/record.url?scp=85141463278&partnerID=8YFLogxK
U2 - 10.1038/s41567-022-01808-4
DO - 10.1038/s41567-022-01808-4
M3 - Article
AN - SCOPUS:85141463278
SN - 1745-2473
SP - 52
EP - 60
JO - Nature Physics
JF - Nature Physics
ER -