Single-molecule magnetic tweezers experiments performed in the past few years report a clear deviation of the effective torsional stiffness of DNA from the predictions of the twistable worm-like chain model. Here we show that this discrepancy can be resolved if a coupling term between bending and twisting is introduced. \pm  Although the existence of such an interaction was predicted more than two decades ago (Marko and Siggia, Macromol. 27, 981 (1994)), its effect on the static and dynamical properties of DNA has been largely unexplored. Our analysis yields a twist-bend coupling constant of G=50+-10 nm. We show that the introduction of twist-bend coupling requires a re-tuning of the other elastic parameters of DNA , in particular for the intrinsic bending stiffness .
Recent magnetic tweezers experiments have reported systematic deviations of the twist response of double-stranded DNA from the predictions of the twistable worm-like chain model. Here we show , by means of analytical results and computer simulations, that these discrepancies can be resolved if a coupling between twist and bend is introduced. We obtain an estimate of 40\pm 10 nm for the twist-bend coupling constant. Our simulations are in good agreement with high-resolution, magnetic-tweezers torque data. Although the existence of twist-bend coupling was predicted long ago (Marko and Siggia, Macromolecules 27, 981 (1994)), its effects on the mechanical properties of DNA have been so far largely unexplored. We expect that this coupling plays an important role in several aspects of DNA statics and dynamics .
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Single-molecule
Recent
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performed in the past few years report a clear deviation of the effective torsional stiffness of
have reported systematic deviations of the twist response of double-stranded
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that this discrepancy
, by means of analytical results and computer simulations, that these discrepancies
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term between bending and twisting
between twist and bend
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We obtain an estimate of 40
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10 nm for the twist-bend coupling constant. Our simulations are in good agreement with high-resolution, magnetic-tweezers torque data.
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such an interaction was predicted more than two decades
twist-bend coupling was predicted long
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Macromol.
Macromolecules
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effect on the static and dynamical
effects on the mechanical
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has been
have been so far
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Our analysis yields a twist-bend coupling constant of G=50+-10 nm. We show that the introduction of twist-bend coupling requires a re-tuning of the other elastic parameters of DNA , in particular for the intrinsic bending stiffness
We expect that this coupling plays an important role in several aspects of DNA statics and dynamics