ChemInform Abstract: Vibrational Analysis of the Retinal Isomers

Stimulated infrared emission in all-trans retinal and wild-type bacteriorhodopsin under CW optical pumping: Studies by FT-IR spectroscopy

“…They almost completely coincide with vibrations that were observed in direct experiments (e.g. in Ramam spectrum or IRabsorption spectrum of retinal's isomers) or obtained on the basis of theoretical considerations [40][41][42]. This is the first detail vibrational emission spectrum published because most of the vibronic structure is lost in an electronic emission spectrum [43,44].…”

“…These are believed to arise from a combination of effects including the electronic resonance and biharmonic pumping, considered above. In accordance to [40], the excited state structure of photoexcited retinal molecule may be determined as the structure of all-trans isomer in both spectra. However, an equilibrium excited state geometry produced by near-off-resonant and resonant excitation is different widely.…”

“…The most prominent features in the IR-emission spectra are two groups of three distinct bands located in the high frequency region 2372, 3367, 3677 cm À1 , and in the region between 800 and 1200 cm À1 at 847, 1004, and 1133 cm À1 . The largest vibrational peaks centered at 847, 1004, and 1133 cm À1 are associated with the hydrogen out-of-plane (HOOP) wag, methyl rock (C-CH 3 ), and C-C single bond stretches (CC) normal modes, respectively [40][41][42]. The center position of high frequency band at 2372 cm À1 is displayed in the range of O-H, N-H, and C-H stretching vibrations.…”

A Photochromic Histidine Kinase Rhodopsin (HKR1) That Is Bimodally Switched by Ultraviolet and Blue Light

“…Because the resonance Raman spectra are sensitive to both 13-cis/trans and 15-syn/anti isomerization (Fig. 5), the excellent agreement between the Raman spectra of Rh-UV and the BR-M410 photocycle intermediate points to a 13-cis configuration of the RSB with an anti conformation of the C ϭ N bond (13-cis,15-anti) (34,35). There are no indications for contributions by an alltrans chromophore because the respective characteristic marker bands, such as a distinct band at 1153 cm Ϫ1 , are not detectable in the Raman spectrum (34).…”

Applications

“…46 Optical micrograph of a cholesterol-bilirubin gallstone. Since Raman spectroscopic studies on them have been reviewed extensively, only the references are cited: hydroporphyrins and chlorophylls(84,85), flavins(86)(87)(88), iron-sulfur proteins(89,90), metaltyrosinate proteins(91), visual pigments and bacterial rhodopsin(92)(93)(94), photosynthesis(95), viruses and nucelproteins(96,97), membranes(98,99) enzyme-substrate reactions(100)(101)(102), and medical applications(103). cholesterol-bilirubin gallstone by using the MOLE and FT-IR.Figure 4-46 is a micrograph showing its layered structure.…”