Vibrational Spectrum of the J-625 Intermediate in the Room Temperature Bacteriorhodopsin Photocycle
| Autor: | Laszlo Ujj, Yidong Zhou, George H. Atkinson |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry A. 104:4130-4139 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/jp9918306 |
| Popis: | The vibrational spectrum (800−1700 cm-1 region) of the J-625 intermediate, formed within 200−500 fs (3.5 ps decay time to K-590) in the room-temperature bacteriorhodopsin (BR) photocycle, is measured via picosecond time-resolved coherent anti-Stokes Raman spectroscopy (PTR/CARS). An examination of the excitation conditions and BR photocycle kinetics, as well as the vibrational CARS data, convincingly demonstrates that these PTR/CARS spectra can be quantitatively analyzed in terms of primarily BR-570 and J-625 by using third-order nonlinear susceptibility (χ(3)) relationships. The resultant background-free (Lorentzian line shapes) CARS spectrum contains 24 distinct vibrational features which provide the most complete structural characterization of J-625 yet reported. Comparisons of the J-625 vibrational spectrum with those of ground-state BR-570 and the K-590 intermediate show that J-625 maintains some structural similarities with BR-570 while it has a significantly different structure than that of K-590. ... |
| Databáze: | OpenAIRE |
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