Observation of coherent delocalized phonon-like modes in DNA under physiological conditions

Underdamped terahertz-frequency delocalized phonon-like modes have long been suggested to play a role in the biological function of DNA. Such phonon modes involve the collective motion of many atoms and are prerequisite to understanding the molecular nature of macroscopic conformational changes and...

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Bibliographic Details
Published in:Nature communications 2016-06, Vol.7 (1), p.11799-11799, Article 11799
Main Authors: González-Jiménez, Mario, Ramakrishnan, Gopakumar, Harwood, Thomas, Lapthorn, Adrian J., Kelly, Sharon M., Ellis, Elizabeth M., Wynne, Klaas
Format: Article
Language:English
Subjects:
140/125
140/133
639/638/440/56
639/638/45/147
Acids
Aqueous solutions
DNA - chemistry
Humanities and Social Sciences
Hydrogen Bonding
Hydrogen bonds
Investigations
multidisciplinary
Neutrons
Oligodeoxyribonucleotides - chemistry
Phonons
Physiology
Science
Science (multidisciplinary)
Spectrum Analysis
Vibration
Water - chemistry
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Summary:Underdamped terahertz-frequency delocalized phonon-like modes have long been suggested to play a role in the biological function of DNA. Such phonon modes involve the collective motion of many atoms and are prerequisite to understanding the molecular nature of macroscopic conformational changes and related biochemical phenomena. Initial predictions were based on simple theoretical models of DNA. However, such models do not take into account strong interactions with the surrounding water, which is likely to cause phonon modes to be heavily damped and localized. Here we apply state-of-the-art femtosecond optical Kerr effect spectroscopy, which is currently the only technique capable of taking low-frequency (GHz to THz) vibrational spectra in solution. We are able to demonstrate that phonon modes involving the hydrogen bond network between the strands exist in DNA at physiologically relevant conditions. In addition, the dynamics of the solvating water molecules is slowed down by about a factor of 20 compared with the bulk. Terahertz-frequency vibrational modes are thought to play a key role for DNA biological functions, yet observation of these fluctuations in solution has proven difficult so far. Here, the authors use femtosecond optical Kerr-effect spectroscopy to demonstrate their existence in physiologically relevant conditions.
ISSN:2041-1723
2041-1723
DOI:10.1038/ncomms11799