| Autor: |
George H. Atkinson, Halina Abramczyk, Andrew C. Terentis, Laszlo Ujj |
| Rok vydání: |
2005 |
| Předmět: |
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| Zdroj: |
Chemical Physics. 313:51-62 |
| ISSN: |
0301-0104 |
| Popis: |
A new model of the primary events of the bacteriorhodopsin (BR) photocycle is derived from the analysis of vibrational spectroscopic data obtained from native BR (BR-570) and three artificial BR pigments containing structurally modified retinals with carbon rings bridging specific C–C and C C bonds (BR6.11, BR6.9, and BR5.12). Vibrational spectra from the ground-states and from picosecond intermediates appearing in the respective photo-reactions are measured by coherent anti-Stokes Raman spectroscopy (CARS). Special attention is given to an analysis of the time-dependent bandwidth changes in vibrational bands assigned to the C C stretching and hydrogen-out-of-plane (HOOP) modes. The bandwidth analysis reveals an intramolecular, vibrational dephasing mechanism in the lowest-energy electronic excited state, involving a coupling between out-of-plane motion along the retinal backbone and C C stretching modes. The mode-selective coupling plays a significant role as a precursor to the all- trans → 13- cis isomerization in BR and accounts for primary events in the BR photocycle not previously demonstrated. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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