%0 Journal Article
%A Bonilla, L.L.
%A Carpio, Ana
%A Prados, A.
%T Protein unfolding and refolding as transitions through virtual states
%D 2014
%@ 0295-5075
%U https://hdl.handle.net/20.500.14352/33867
%X Single-molecule atomic force spectroscopy probes elastic properties of titin, ubiquitin and other relevant proteins. We explain bioprotein folding dynamics under both length- and force-clamp by modeling polyprotein modules as particles in a bistable potential, weakly connected by harmonic spring linkers. Multistability of equilibrium extensions provides the characteristic sawtooth force-extension curve. We show that abrupt or stepwise unfolding and refolding under force-clamp conditions involve transitions through virtual states (which are quasi-stationary domain configurations) modified by thermal noise. These predictions agree with experimental observations.
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