Dresden 2011 – scientific programme
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MO: Fachverband Molekülphysik
MO 9: Femtosecond Spectroscopy II
MO 9.3: Talk
Tuesday, March 15, 2011, 11:15–11:30, TOE 317
Vibrational energy flow in artificial amino acids investigated by 2D-IR spectroscopy — •Henrike Müller-Werkmeister1, Yun-Liang Li1, Eliza-Beth W. Lerch1, Andreas T. Messmer1, Damien Bigourd1,2, Silvia Eger3, Andreas Marx3, and Jens Bredenbeck1 — 1Institute for Biophysics, Goethe-University Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt — 2Commissariat à l'énergie atomique, Centre d'études scientifiques et techniques d'Aquitaine, Le Barp, France — 3Institute for Organic Chemistry, University Konstanz, 78457 Konstanz
The unique combination of recent protein engineering methods with ultrafast 2D-IR spectroscopy shows great promise for the investigation of biomolecular dynamics on picosecond timescales. Site-selective, in vivo incorporation of artificial amino acids, absorbing in IR spectral regions well-separated from other protein vibrations will allow for the direct observation of energy flow in real-time. Here, we investigate the spectral properties of azido- and nitrile-labeled amino acids. Two-colour 2D-IR spectroscopy is shown to permit direct determination of energy transfer times between different functional groups in these artificial amino acids. The simultaneous use of two, independently tunable, optical parametric amplifiers for IR-light generation enables us to observe time-dependent cross peaks between vibrations widely separated in the spectrum. A clear correlation between energy transfer time and distance between functional groups is observed. Thus 2C-2D-IR provides information to support the assignment of vibrational absorption bands. Additional DFT-calculations prove the experimental results.