Picosecond dynamics of bacteriorhodopsin, probed by time-resolved infrared spectroscopy. |
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Authors: | R Diller M Iannone B R Cowen S Maiti R A Bogomolni R M Hochstrasser |
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Affiliation: | Department of Chemistry, University of Pennsylvania, Philadelphia 19104. |
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Abstract: | The photoinduced reaction cycle of bacteriorhodopsin (BR) has been studied by means of a recently developed picosecond infrared spectroscopic method at ambient temperature. BR - K difference spectra between 1560 and 1700 cm-1 have been recorded at delay times from 100 ps to 14 ns. The spectrum remains unchanged during this period. The negative difference OD band at 1660 cm-1 indicates the peptide backbone responds within 50 ps. A survey in the region of carboxylic side chain absorption around 1740 cm-1 reveals that perturbations of those groups, present in low-temperature FTIR spectra, are not observable within 10 ns, suggesting a slow conformational change. |
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