Theories that are used to extract energy-landscape information from single-molecule pulling experiments in biophysics are all invariably based on Kramers' theory of the thermally activated escape rate from a potential well. As is well known, this theory recovers the Arrhenius dependence of the rate on the barrier energy and crucially relies on the assumption that the barrier energy is much larger than k_BT (limit of comparatively low thermal fluctuations). As was shown already in Dudko et al. [Phys. Rev. Lett. 96, 108101 (2006)PRLTAO0031-900710.1103/PhysRevLett.96.108101], this approach leads to the unphysical prediction of dissociation time increasing with decreasing binding energy when the latter is lowered to values comparable to k_BT (limit of large thermal fluctuations). We propose a theoretical framework (fully supported by numerical simulations) which amends Kramers' theory in this limit and use it to extract the dissociation rate from single-molecule experiments where now predictions are physically meaningful and in agreement with simulations over the whole range of applied forces (binding energies). These results are expected to be relevant for a large number of experimental settings in single-molecule biophysics.

Dissociation rates from single-molecule pulling experiments under large thermal fluctuations or large applied force / M. Abkenar, T.H. Gray, A. Zaccone. - In: PHYSICAL REVIEW. E. - ISSN 2470-0045. - 95:4(2017 Apr 28). [10.1103/PhysRevE.95.042413]

Dissociation rates from single-molecule pulling experiments under large thermal fluctuations or large applied force

A. Zaccone
2017-04-28

Abstract

Theories that are used to extract energy-landscape information from single-molecule pulling experiments in biophysics are all invariably based on Kramers' theory of the thermally activated escape rate from a potential well. As is well known, this theory recovers the Arrhenius dependence of the rate on the barrier energy and crucially relies on the assumption that the barrier energy is much larger than k_BT (limit of comparatively low thermal fluctuations). As was shown already in Dudko et al. [Phys. Rev. Lett. 96, 108101 (2006)PRLTAO0031-900710.1103/PhysRevLett.96.108101], this approach leads to the unphysical prediction of dissociation time increasing with decreasing binding energy when the latter is lowered to values comparable to k_BT (limit of large thermal fluctuations). We propose a theoretical framework (fully supported by numerical simulations) which amends Kramers' theory in this limit and use it to extract the dissociation rate from single-molecule experiments where now predictions are physically meaningful and in agreement with simulations over the whole range of applied forces (binding energies). These results are expected to be relevant for a large number of experimental settings in single-molecule biophysics.
Computer Simulation; Time Factors; Mechanical Phenomena; Models, Molecular; Thermodynamics
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
Settore FIS/03 - Fisica della Materia
Article (author)
File in questo prodotto:
File Dimensione Formato  
LY14704_resub.pdf

accesso aperto

Tipologia: Post-print, accepted manuscript ecc. (versione accettata dall'editore)
Dimensione 603.72 kB
Formato Adobe PDF
603.72 kB Adobe PDF Visualizza/Apri
PhysRevE.95.042413.pdf

accesso riservato

Tipologia: Publisher's version/PDF
Dimensione 332.3 kB
Formato Adobe PDF
332.3 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/610003
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 16
  • ???jsp.display-item.citation.isi??? 13
social impact