Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 44: DNA/RNA and related enzymes
BP 44.6: Vortrag
Donnerstag, 19. März 2015, 16:30–16:45, H 1058
Vibrational dynamics and hydration of the DNA backbone — •Biswajit Guchhait, Yingliang Liu, Rene Costard, Torsten Siebert, and Thomas Elsaesser — Max-Born-Institut für Nichtlinear Opitk und Kurzzeitspektroskopie, Max-Born-Str. 2a, 12489 Berlin, Germany
The DNA double helix and its aqueous environment display structural dynamics on the ultrafast time-scale of molecular motions. Two-dimensional (2D) infrared spectroscopy is employed in a frequency range from 950 to 1300 cm−1 to map and discern the vibrational excitations of the fully hydrated DNA backbone, their couplings and the interactions with the surrounding water shell. The mutual couplings and corresponding delocalized nature of vibrational modes of the phosphate group, phosphodiester linkage and furanose ring structure within the backbone are evident from the rich cross peak pattern observed in the 2D spectra. The couplings further facilitate a picosecond transfer of vibrational energy from the phosphate to the sugar linkage and ring modes. The phosphate modes further play a key role for the interaction with the surrounding water shell, where structural fluctuations of interfacial water are limited and slowed down compared to bulk H 2O. This behavior is attributed to steric hindrance and the action of strong electric fields at the interface.