The terahertz dynamics of human cells of the U937 line and their chromatin has been investigated by high-resolution inelastic X-ray scattering. To highlight its dynamical features in situ, nuclear DNA has been stained by uranyl-acetate salt. The general behavior of the collective dynamics of the whole cell is quite similar to that of bulk water, with a nearly wavevector-independent branch located at about 5 meV and a propagating mode with a linear trend corresponding to a speed of sound of 2900 +/- 100 m/s. We provide the first experimental evidence for the existence of two branches also in the dispersion curves of chromatin. The high-energy mode displays an acoustic-like behavior with a sound velocity similar to unstained cells, but in this case the branch likely originates from the superposition of intramolecular DNA optic modes. A low-energy optic-like branch, distinctive of the chromatin moiety, is found at about 2.5 meV.
Terahertz dynamics in human cells and their chromatin / Longo M.; Marconi M.; Orecchini A.; Petrillo C.; Monaco G.; Calvitti M.; Pirisinu I.; Romani R.; Sacchetti F.; Sebastiani F.; Zanatta M.; Paciaroni A.. - In: THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS. - ISSN 1948-7185. - STAMPA. - 5:(2014), pp. 2177-2181. [10.1021/jz500918w]
Terahertz dynamics in human cells and their chromatin
Sebastiani F.;
2014
Abstract
The terahertz dynamics of human cells of the U937 line and their chromatin has been investigated by high-resolution inelastic X-ray scattering. To highlight its dynamical features in situ, nuclear DNA has been stained by uranyl-acetate salt. The general behavior of the collective dynamics of the whole cell is quite similar to that of bulk water, with a nearly wavevector-independent branch located at about 5 meV and a propagating mode with a linear trend corresponding to a speed of sound of 2900 +/- 100 m/s. We provide the first experimental evidence for the existence of two branches also in the dispersion curves of chromatin. The high-energy mode displays an acoustic-like behavior with a sound velocity similar to unstained cells, but in this case the branch likely originates from the superposition of intramolecular DNA optic modes. A low-energy optic-like branch, distinctive of the chromatin moiety, is found at about 2.5 meV.File | Dimensione | Formato | |
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