title: Long-Range Vibrational Dynamics Are Directed by Watson-Crick Base Pairing in Duplex DNA.
abstract: Ultrafast two-dimensional infrared (2D-IR) spectroscopy of a 15-mer A-T DNA duplex in solution has revealed structure-dependent vibrational coupling and energy transfer processes linking bases with the sugar-phosphate backbone. Duplex melting induces significant changes in the positions of off-diagonal peaks linking carbonyl and ring-stretching vibrational modes of the adenine and thymine bases with vibrations of the phosphate group and phosphodiester linkage. These indicate that Watson-Crick hydrogen bonding and helix formation lead to a unique vibrational coupling arrangement of base vibrational modes with those of the phosphate unit. On the basis of observations from time-resolved 2D-IR data, we conclude that rapid energy transfer processes occur between base and backbone, mediated by additional modes located on the deoxyribose moiety within the same nucleotide. These relaxation dynamics are insensitive to duplex melting, showing that efficient intramolecular energy relaxation to the solvent via the phosphate groups is the key to excess energy dissipation in both single- and double-stranded DNA.
authors.affiliation: Department of Physics, University of Strathclyde, SUPA , 107 Rottenrow East, Glasgow G4 0NG, U.K.
authors.forename: Gordon
authors.initials: G
authors.lastname: Hithell
authors.affiliation: Department of Physics, University of Strathclyde, SUPA , 107 Rottenrow East, Glasgow G4 0NG, U.K.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Shaw
authors.affiliation: Research Complex at Harwell, Harwell Science and Innovation Campus, STFC Central Laser Facility , Didcot OX11 0QX, U.K.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Donaldson
authors.affiliation: Research Complex at Harwell, Harwell Science and Innovation Campus, STFC Central Laser Facility , Didcot OX11 0QX, U.K.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Greetham
authors.affiliation: Research Complex at Harwell, Harwell Science and Innovation Campus, STFC Central Laser Facility , Didcot OX11 0QX, U.K.
authors.forename: Michael
authors.initials: M
authors.lastname: Towrie
authors.affiliation: Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.
authors.forename: Glenn A
authors.initials: GA
authors.lastname: Burley
authors.affiliation: Research Complex at Harwell, Harwell Science and Innovation Campus, STFC Central Laser Facility , Didcot OX11 0QX, U.K.
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Parker
authors.affiliation: Department of Physics, University of Strathclyde, SUPA , 107 Rottenrow East, Glasgow G4 0NG, U.K.
authors.forename: Neil T
authors.initials: NT
authors.lastname: Hunt
mesh_terms: D020029:Base Pairing; D004247:DNA / Q000737:chemistry*; D004735:Energy Transfer; D013055:Spectrophotometry, Infrared; D013816:Thermodynamics; D014732:Vibration
chemical_list: D004247:DNA