dorsal/arxiv
View SchemaA two-state kinetic model for the unfolding of single molecules by mechanical force
| Authors | F. Ritort, C. Bustamante, I. Tinoco, Jr. |
|---|---|
| Categories | |
| ArXiv ID | physics/0210063 |
| URL | https://arxiv.org/abs/physics/0210063 |
| DOI | 10.1073/pnas.172525099 |
| Journal | PNAS 2002;99 13544-13548 |
Abstract
We investigate the work dissipated during the irreversible unfolding of single molecules by mechanical force, using the simplest model necessary to represent experimental data. The model consists of two levels (folded and unfolded states) separated by an intermediate barrier. We compute the probability distribution for the dissipated work and give analytical expressions for the average and variance of the distribution. To first order, the amount of dissipated work is directly proportional to the rate of application of force (the loading rate), and to the relaxation time of the molecule. The model yields estimates for parameters that characterize the unfolding kinetics under force in agreement with those obtained in recent experimental results (Liphardt, J., et al. (2002) {\em Science}, {\bf 296} 1832-1835). We obtain a general equation for the minimum number of repeated experiments needed to obtain an equilibrium free energy, to within $k_BT$, from non-equilibrium experiments using the Jarzynski formula. The number of irreversible experiments grows exponentially with the ratio of the average dissipated work, $\bar{\Wdis}$, to $k_BT$.}
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"abstract": "We investigate the work dissipated during the irreversible unfolding of\nsingle molecules by mechanical force, using the simplest model necessary to\nrepresent experimental data. The model consists of two levels (folded and\nunfolded states) separated by an intermediate barrier. We compute the\nprobability distribution for the dissipated work and give analytical\nexpressions for the average and variance of the distribution. To first order,\nthe amount of dissipated work is directly proportional to the rate of\napplication of force (the loading rate), and to the relaxation time of the\nmolecule. The model yields estimates for parameters that characterize the\nunfolding kinetics under force in agreement with those obtained in recent\nexperimental results (Liphardt, J., et al. (2002) {\\em Science}, {\\bf 296}\n1832-1835). We obtain a general equation for the minimum number of repeated\nexperiments needed to obtain an equilibrium free energy, to within $k_BT$, from\nnon-equilibrium experiments using the Jarzynski formula. The number of\nirreversible experiments grows exponentially with the ratio of the average\ndissipated work, $\\bar{\\Wdis}$, to $k_BT$.}",
"arxiv_id": "physics/0210063",
"authors": [
"F. Ritort",
"C. Bustamante",
"I. Tinoco, Jr."
],
"categories": [
"physics.bio-ph",
"cond-mat.soft"
],
"doi": "10.1073/pnas.172525099",
"journal_ref": "PNAS 2002;99 13544-13548",
"title": "A two-state kinetic model for the unfolding of single molecules by mechanical force",
"url": "https://arxiv.org/abs/physics/0210063"
},
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