Forced Kramers escape in single-molecule pulling experiments.
The pulling-induced rupture of noncovalent bonds is studied by the overdamped Kramers theory with full account of a time-varying barrier. Mechanic pulling reduces the energy barrier and leads to loading-rate dependence of the rupture force F(u)(F(t)). Tested against Langevin dynamics, four distinct regimes are identified, including kinetic dominant, weak pulling, strong pulling, and mechanic pulling dominant. Asymptotic analyses show that F(u) approximately ln F(t) in weak pulling regime and becomes 1-(F(u)F(c)) approximately [ln(F(t))E(b)](23) in strong pulling regime. Kinetic informations such as activation energy E(b) and critical force F(c) were extracted from pulling experiments for biotin-streptavidin complex.
Sheng
Yu-Jane
YJ
Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China.
Jiang
Shaoyi
S
Tsao
Heng-Kwong
HK
D001710:Biotin / Q000737:chemistry; D002627:Chemistry, Physical / Q000379:methods*; D003198:Computer Simulation; D006801:Humans; D007700:Kinetics; D008024:Ligands; D015233:Models, Statistical; D019809:Streptavidin / Q000737:chemistry; D013314:Stress, Mechanical; D013816:Thermodynamics
D008024:Ligands; D001710:Biotin; D019809:Streptavidin