Vibrational spectra of room-temperature rhodopsin: concentration dependence in picosecond resonance coherent anti-Stokes Raman scattering.
The vibrational degrees of freedom of room-temperature rhodopsin (RhRT), the central trans-membrane protein in vision, are measured at room temperature by picosecond resonance coherent anti-Stokes Raman scattering (PR/CARS). High signal-to-noise PR/CARS data for the ethylenic stretching, Schiff base, and hydrogen-out-of-plane modes of the retinal chromophore are quantitatively analyzed via third-order susceptibility relationships. The accurate determination of spectral features permit the PR/CARS bandshapes to be analyzed as a function of RhRT concentration, an essential factor in using picosecond time-resolved CARS techniques to measure the vibrational spectroscopy of picosecond intermediates in the RhRT photosequence. Of particular importance is the recognition that PR/CARS bandshapes are sensitive functions of both the chromophore concentration and the excitation wavelength, as measured relative to the absorption spectra of specific chromophores (static and transient).
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Department of Chemistry, University of Arizona, Tucson 85721, USA.
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Atkinson
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D000818:Animals; D002417:Cattle; D007700:Kinetics; D011487:Protein Conformation; D012172:Retinaldehyde / Q000378:metabolism; D012243:Rhodopsin / Q000737:chemistry* / Q000378:metabolism*; D012542:Scattering, Radiation; D013059:Spectrum Analysis, Raman / Q000379:methods; D013696:Temperature; D013997:Time Factors
D012243:Rhodopsin; D012172:Retinaldehyde