Retinal proteins

Sensory rhodopsin (sR) and proteorhodopsin 4.12.1. Sensory rhodopsin Halobacteria contain a family of four retinal proteins, bR, halorhodopsin (hR), sensory rhodopsin I (sR I), and phobor-hodopsin (pR or sensory rhodopsin II, sR II), which carry two distinct functions through common photochemical reactions. In particular, bR... 

Membrane proteins other than retinal proteins... 

Hampp, N. (2000) Bacteriorhodopsin as photochromic retinal protein for optical memories. Chemical Reviews, 100, 1755-1776. 

M. Wanko, M. Hoffmann, P. Strodel, A. Koslowski, W. Thiel, F. Neese, T. Frauenheim, and M. Elstner. Calculating absorption shifts for retinal proteins computational challenges, J. Phys. Chem. B, 109 3606-3615 (2005). 

Tezel, G., Yang, X., and Cai,J. (2005). Proteomic identification of oxidatively modified retinal proteins in a chronic pressure-induced rat model of glaucoma. Invest. Ophthalmol. Vis. Sci. 46, 3177—3187. 

Rundle, D. R., Rajala, R. V., and Anderson, R. E. 2002. Characterization of Type I and Type II myristoyl-CoA protein N-myristoyltransferases with the Acyl-CoAs found on heterogeneously acylated retinal proteins. Exp. Eye Res. 75 87-97. 

Adamus G, Ren G, Weleber RG. Autoantibodies against retinal proteins in paraneoplastic and autoimmune retinopathy. BMC Ophthalmol 2004 4-5 1-9. 

Phytochrome, Photosynthetic Reaction Center, Electron Transfer, Color-tuning Mechanism, Retinal Protein, Green Fluorescent Protein, Firefly Luciferase... 

CT excitation energy. The amount of the blue-shift was qualitatively explained by the change in ES potential along the skeleton. This is a general feature seen in the retinal protein including PSB. 

The authors thank Prof. S. Hayashi (Kyoto University) for fruitful collaborations in the study of the color-tuning mechanism of retinal proteins. This study was supported by a Grant-in-Aid for Creative Scientific Research from the Ministry of Education, Culture, Sports, Sciences, and Technology of Japan. A part of the computations was performed in the Research Center for Computational Science, Okazaki, Japan. 

Oesterhelt, D. (1998). The structure and mechanism of the family of retinal proteins from halophilic archaea. Curr. Opin. Struct. Biol. 8, 489-500. 

Since the pioneering work by Cotton et al. on heme proteins (Cotton et al., 1980), surface enhanced resonance Raman spectroscopy (SERRS), Sec. 6.1, has been used to study a large variety of biomolecules, such as retinal proteins (Nabiev et al., 1985), flavoproteins (Coperland et al., 1984 Holt and Cotton, 1987), chlorophylls (Cotton and Van Duyne, 1982 Hildebrandt and Spiro, 1988), and oxyhemoglobins (de Groot and Hesters, 1987). The advantages of this technique include low sample concentration and fluorescence quenching. The main question is whether or not the native structure and function of the molecule is preserved on the metal surface. 

Photoreceptor Pigments. There have been several reviews on the structures, photochemistry, and functioning of the retinal-protein photoreceptor pigments involved in the processes of visionand in the purple membrane of Halobacteria (bacteriorhodopsin). ° ° In addition to the papers quoted earlier on the spectroscopy of these pigments, many other reports have appeareddealing with rhodopsin and intermediates in its photocycle, especially photochemistry, chromophore-protein conformation and binding, and reaction kinetics. Similar studies on bacteriorhodopsin have also been described." "-"" ... 

Roepman, R., Schick, D. and Ferreira, PA. (2000b) Isolation of retinal proteins that interact with retinitis pigmentosa GTPase regulator by interaction trap screen in yeast. Meth. Enzymol. 316, 688-704. 

These researches have been carried out starting from the shorter conjugated system found in a-ionone and related products (Xmax 225 m/i) and proceeding to the complex systems found in retinol (Xmax 325 m u) and retinal (Xmax 380 m u). As to the still longer conjugations, represented by the combination retinal-protein, just a brief abstract of the theories about the role of retinal in vision will be reported. Special emphasis will be placed on NMR spectroscopy which enabled us to follow quite accurately the transformation of conjugated chains. 

Bacteriorhodopsin and halorhodopsin are unique energy transducers characteristic of halobacteria and absent in other living cells. The structural and functional aspects of these retinal proteins will be considered in Chapter 6 of this volume. Here we would like to review only two aspects of the problem, namely, the mechanism of the light-induced transmembrane eharge displacement by bacteriorhodopsin, and the involvement of bacteriorhodopsin in photoreception, mediated by a sensor. 

When bacteriorhodopsin was discovered in 1971, its similarity to the visual rhodopsin in the chromophore structure (retinal), the primary light-induced event (retinal isomerization) and the photocycle (short-wavelength intermediate formation) impelled the authors to suggest that this novel retinal protein is somehow involved in photoreception [1]. Such a suggestion seemed reasonable since halobacteria are known to change their direction of swimming in response to a light stimulus. 

However, subsequent studies on halobacterial retinal proteins seemed to argue against the photoreceptor function of bacteriorhodopsin. It was found that (i) bacteriorhodopsin operates as a light-driven H pump and (ii) in the same halobacteria there are two other retinal proteins, i.e., sensory rhodopsin I and sensory rhodopsin II (also known as photorhodopsin) which are specialized in photoreception rather than in H pumping, being present in much smaller amounts than bacteriorhodopsin [36-43]. It was shown that... 

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