title: Observation of coherent delocalized phonon-like modes in DNA under physiological conditions.
abstract: 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.
authors.affiliation: School of Chemistry, WestCHEM, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Mario
authors.initials: M
authors.lastname: González-Jiménez
authors.affiliation: School of Chemistry, WestCHEM, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Gopakumar
authors.initials: G
authors.lastname: Ramakrishnan
authors.affiliation: Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Harwood
authors.affiliation: School of Chemistry, WestCHEM, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Lapthorn
authors.affiliation: Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Kelly
authors.affiliation: Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Ellis
authors.affiliation: School of Chemistry, WestCHEM, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Klaas
authors.identifier: 0000-0002-5305-5940
authors.initials: K
authors.lastname: Wynne
mesh_terms: D004247:DNA / Q000737:chemistry*; D006860:Hydrogen Bonding; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D060739:Phonons; D013057:Spectrum Analysis; D014732:Vibration; D014867:Water / Q000737:chemistry
chemical_list: D009838:Oligodeoxyribonucleotides; D014867:Water; D004247:DNA