Hithell, G., González-Jiménez, M. , Greetham, G. M., Donaldson, P. M., Towrie, M., Parker, A. W., Burley, G. A., Wynne, K. and Hunt, N. T. (2017) Ultrafast 2D-IR and optical Kerr effect spectroscopy reveal the impact of duplex melting on the structural dynamics of DNA. Physical Chemistry Chemical Physics, 16(19), pp. 10333-10342. (doi: 10.1039/C7CP00054E)
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Abstract
Changes in the structural and solvation dynamics of a 15mer AT DNA duplex upon melting of the double-helix are observed by a combination of ultrafast two-dimensional infrared (2D-IR) and optical Kerr-effect (OKE) spectroscopies. 2D-IR spectroscopy of the vibrational modes of the DNA bases reveal signature off-diagonal peaks arising from coupling and energy transfer across Watson–Crick paired bases that are unique to double-stranded DNA (ds-DNA). Spectral diffusion of specific base vibrational modes report on the structural dynamics of the duplex and the minor groove, which is predicted to contain a spine of hydration. Changes in these dynamics upon melting are assigned to increases in the degree of mobile solvent access to the bases in single-stranded DNA (ss-DNA) relative to the duplex. OKE spectra exhibit peaks that are assigned to specific long-range phonon modes of ds- and ss-DNA. Temperature-related changes in these features correlate well with those obtained from the 2D-IR spectra although the melting temperature of the ds-DNA phonon band is slightly higher than that for the Watson–Crick modes, suggesting that a degree of long-range duplex structure survives the loss of Watson–Crick hydrogen bonding. These results demonstrate that the melting of ds-DNA disrupts helix-specific structural dynamics encompassing length scales ranging from mode delocalisation in the Watson–Crick base pairs to long-range phonon modes that extend over multiple base pairs and which may play a role in molecular recognition of DNA.
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Gonzalez Jimenez, Dr Mario and Burley, Dr Glenn and Wynne, Professor Klaas |
Authors: | Hithell, G., González-Jiménez, M., Greetham, G. M., Donaldson, P. M., Towrie, M., Parker, A. W., Burley, G. A., Wynne, K., and Hunt, N. T. |
College/School: | College of Science and Engineering > School of Chemistry |
Journal Name: | Physical Chemistry Chemical Physics |
Publisher: | Royal Society of Chemistry |
ISSN: | 1463-9076 |
ISSN (Online): | 1463-9084 |
Published Online: | 06 April 2017 |
Copyright Holders: | Copyright © 2017 Royal Society of Chemistry |
First Published: | First published in Physical Chemistry Chemical Physics 19(16):10333-10342 |
Publisher Policy: | Reproduced under a Creative Commons License |
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