Resonance Raman studies of bovine and octopus visual pigments.
Item
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Title
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Resonance Raman studies of bovine and octopus visual pigments.
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Identifier
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AAI9530882
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identifier
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9530882
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Creator
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Huang, Liewen.
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Contributor
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Adviser: Robert H. Callender
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Date
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1995
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biophysics, General | Physics, Optics | Health Sciences, Ophthalmology | Biology, Animal Physiology | Biology, Neuroscience
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Abstract
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We have regenerated bovine and octopus visual pigments with retinals containing isotopic labels at three positions, i.e., 8-{dollar}\sp{13}{dollar}C-11,12-D{dollar}\sb2{dollar}, 10-{dollar}\sp{13}{dollar}C-11,12-D{dollar}\sb2{dollar}, 11-{dollar}\sp{13}{dollar}C-11,12-D{dollar}\sb2{dollar}, 14-{dollar}\sp{13}{dollar}C-11,12-D{dollar}\sb2{dollar}, for the studies of bound chromophore ethylenic and Schiff base vibrational modes by resonance Raman spectroscopy. Also regenerated were octopus visual pigments with singly or doubly {dollar}\sp{13}{dollar}C labeled retinals, i.e., 9-{dollar}\sp{13}{dollar}C, 10,11-{dollar}\sp{13}{dollar}C{dollar}\sb2{dollar}, 12,13-{dollar}\sp{13}{dollar}C{dollar}\sb2{dollar}, 13-{dollar}\sp{13}{dollar}C, 14,15-{dollar}\sp{13}{dollar}C{dollar}\sb2{dollar}, 14,15-{dollar}\sp{13}{dollar}C{dollar}\sb2{dollar}-ND, for the studies of vibrational modes in the fingerprint region. We have analyzed the resonance Raman spectra based upon the observation of the response of individual bands in the spectrum of rhodopsin, isorhodopsin, or bathorhodopsin to a particular label. The observed peaks in the fingerprint and ethylenic regions have been tentatively assigned to specific C-C and C=C stretches.;We have also studied a model retinal protonated Schiff base analog and its isotopically labeled derivatives as well as calculations using ab initio methods. Based on the vibrational analysis, new criteria to determine the Schiff base C=N configuration from Raman spectroscopy have been developed, and the C=N configuration in octopus rhodopsin, isorhodopsin and bathorhodopsin has been determined.;We have continued the resonance Raman study of the Schiff base hydrogen/deuterium exchange for rhodopsin and bacteriorhodopsin by employing the continuous-flow experiment. The exchange of a deuteron on the Schiff base with a proton is very fast, with half-times of 6.9 {dollar}\pm{dollar} 0.9 and 1.3 {dollar}\pm{dollar} 0.3 ms for rhodopsin and bacteriorhodopsin, respectively, faster than the proton-deuteron exchange rate of a protonated Schiff base in aqueous solution (16 {dollar}\pm{dollar} 2 ms). This anomalous result can be understand if a structural water molecule (or molecules) is present next to the protonated Schiff base in the two pigments.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
