Force spectroscopy of single multidomain biopolymers: a master equation approach.
Experiments using atomic force microscopy for unfolding single multidomain biopolymers cover a broad range of time scales from equilibrium to non-equilibrium. A master equation approach allows to identify and treat coherently three dynamical regimes for increasing linear ramp velocity: i) an equilibrium regime, ii) a transient regime where refolding events still occur, and iii) a saw-tooth regime without any refolding events. For each regime, analytical approximations are derived and compared to numerically investigated examples. We analyze in the framework of this model also a periodic experimental protocol instead of a linear ramp. In this case, a major simplification arises if the dynamics can be restricted to an effectively two-dimensional subspace. For transitions with an intermediate meta-stable state, like Immunoglobulin27, a refined model allows to extract previously unknown molecular parameters related to this meta-stable state.
Braun
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II. Institut für Theoretische Physik, Universität Stuttgart, 70550, Stuttgart, Germany.
Seifert
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D000465:Algorithms; D001704:Biopolymers / Q000032:analysis / Q000737:chemistry*; D003198:Computer Simulation; D004548:Elasticity; D008846:Micromanipulation / Q000379:methods*; D018625:Microscopy, Atomic Force / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D013314:Stress, Mechanical
D001704:Biopolymers