Abstract
Quantifying the molecular elasticity of DNA is fundamental to our understanding of its biological functions. Recently different groups, through experiments on tailored DNA samples and numerical models, have reported a range of stretching force constants (0.3 to ). However, the most direct, microscopic measurement of DNA stiffness is obtained from the dispersion of its vibrations. A new neutron scattering spectrometer and aligned, wet spun samples have enabled such measurements, which provide the first data of collective excitations of DNA and yield a force constant of . Structural and dynamic order persists unchanged to within 15 K of the melting point of the sample, precluding the formation of bubbles. These findings are supported by large scale phonon and molecular dynamics calculations, which reconcile hard and soft force constants.
- Received 19 October 2010
DOI:https://doi.org/10.1103/PhysRevLett.107.088102
© 2011 American Physical Society