New Measurements of DNA Twist Elasticity

الأصل · EN

The symmetries of the DNA double helix require a new term in its linear response to stress: the coupling between twist and stretch. Recent experiments with torsionally-constrained single molecules give the first direct measurement of this new material parameter. We extract its value from a recent experiment. We also present a very simple microscopic theory predicting a value comparable to the one observed. Finally we sketch the effect of constrained twist on entropic elasticity of DNA arising from the connection between Link, Twist, and Writhe.