title: SPECTRAL METHODS FOR STUDY OF THE G-PROTEIN-COUPLED RECEPTOR RHODOPSIN. I. VIBRATIONAL AND ELECTRONIC SPECTROSCOPY.
abstract: Here we review the application of modern spectral methods for the study of G-protein-coupled receptors (GPCRs) using rhodopsin as a prototype. Because X-ray analysis gives us immobile snapshots of protein conformations, it is imperative to apply spectroscopic methods for elucidating their function: vibrational (Raman, FTIR), electronic (UV-visible absorption, fluorescence) spectroscopies, and magnetic resonance (electron paramagnetic resonance, EPR), and nuclear magnetic resonance, NMR). In the first of the two companion articles, we discuss the application of optical spectroscopy for studying rhodopsin in a membrane environment. Information is obtained regarding the time-ordered sequence of events in rhodopsin activation. Isomerization of the chromophore and deprotonation of the retinal Schiff base leads to a structural change of the protein involving the motion of helices H5 and H6 in a pH-dependent process. Information is obtained that is unavailable from X-ray crystallography, which can be combined with spectroscopic studies to achieve a more complete understanding of GPCR function.
authors.affiliation: St. Petersburg State Medical University, 194100 St. Petersburg, Russia; St. Petersburg State University, 199034 St. Petersburg, Russia; University of Arizona, Tucson, AZ 85721 USA.
authors.forename: A V
authors.initials: AV
authors.lastname: Struts
authors.affiliation: St. Petersburg State Medical University, 194100 St. Petersburg, Russia; St. Petersburg State University, 199034 St. Petersburg, Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Barmasov
authors.affiliation: University of Arizona, Tucson, AZ 85721 USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Brown
keywords: FTIR spectroscopy; G-protein-coupled receptors; Raman spectroscopy; circular dichroism; electronic spectroscopy; fluorescence; linear dichroism; optical spectroscopy; rhodopsin