Wavelength regulation in iodopsin, a cone pigment

Chen, J.G.; Nakamura, Tadashi; Ebrey, Thomas G.; Ok, Hyun; Konno, Katsuhiro; Derguini, Fadila; Nakanishi, Koji; Honig, Barry

doi:10.1016/s0006-3495(89)82871-1

Cited by 30 publications

(32 citation statements)

References 21 publications

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“…Figure 2 shows the absorption spectrum from the protonated Schiff base of 6-s-cis,9-cis-retinal, whose wavelength of maximal sensitivity (Amax) was 467 nm. Absorption spectra of the protonated Schiff-base forms of 11-cis-and 9-cis-retinal were also measured; their maxima were 440 and 439 nm, respectively, in good agreement with published data (see Chen et al 1989 Chromophores were delivered to bleached cones in lipid vesicles (Perlman, Nodes & Pepperberg, 1982;Corson, Cornwall, Crouch & Mani, 1988;Jones, Crouch, Wiggert, Cornwall & Chader, 1990). Vesicles were prepared by drying 50 Al of L-a-phosphatidylcholine (Sigma) under nitrogen, then adding 500fl1 of Ringer or Locke's solution and sonicating on ice until clear, about 10-15 min.…”

Section: Preparation Of Chromophores and Lipid Vehiclessupporting

confidence: 83%

“…Chromophore replacement has also confirmed that part of the opsin shift in bacteriorhodopsin is produced by the protein's twisting the chromophore into the planar 6-s-trans conformation (Harbison, Smith, Pardoen, Courtin, Lugtenburg, Herzfeld, Mathies, Griffin, 1985;Lugtenburg, Muradin-Szweykowska, Heeremans, Pardoen, Harbison, Herzfeld, Smith & Mathies, 1986;van der Steen, Biesheuvel, Mathies & Lugtenburg, 1986). A similar mechanism has been proposed to account for part of the red shift in the chicken cone pigment iodopsin (Chen, Nakamura, Ebrey, Ok, Konno, Derguini, Nakanishi & Honig, 1989).…”

Section: Introductionmentioning

confidence: 77%

“…The AmaXs and opsin shifts for the visual pigments in Figs 5-10 are summarized in Table 2. The maximum for the protonated Schiff base of 3-dehydroretinal was taken as 471 nm (Chen et al 1989). We define the 'planarity factor' as the difference between the opsin shifts of 9-cis-retinal and the locked planar 6-s-cis, 9-cis-retinal analogue.…”

Section: Bleaching and Regenerationmentioning

confidence: 99%

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Effects of modified chromophores on the spectral sensitivity of salamander, squirrel and macaque cones.

Makino

Kraft

Mathies

et al. 1990

The Journal of Physiology

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SUMMARY1. Chemically modified retinal chromophores were used to investigate the mechanisms that produce the characteristic spectral absorptions of cone pigments. Spectral sensitivities of single cones from the salamander, squirrel and macaque retina were determined by electrical recording. The chromophore was then replaced by bleaching the pigment and regenerating it with a retinal analogue.2. Exposing a bleached cone to 9-cis-retinal for a brief period (less than 20 min) caused its flash sensitivity to recover to about 0-2 of the pre-bleach value. Similar exposure to a locked 6-s-cis, 9-cis analogue gave a recovery to about 0 03 of the prebleach value.3. Unlike the flash sensitivity, the saturating photocurrent amplitude often recovered completely after bleaching and regenerating the pigment.4. When the 3-dehydroretinal chromophore in the salamander long-wavelengthsensitive (red) cone was replaced with 1 1-cis-retinal, shortening the conjugated chain in the chromophore, the spectral sensitivity underwent a blue shift of 67 nm. 5. Pigments containing the planar-locked 6-s-cis,9-cis-retinal analogue absorbed at substantially longer wavelength than those containing unmodified 9-cis-retinal. The opsin shift, a measure of the protein's ability to modify the chromophore's absorption, was larger for the locked analogue than for 9-cis-retinal. This suggests that the native chromophore assumes a twisted 6-s-cis conformation in these pigments.6. The spectral sensitivities of red and green macaque cones containing 9-cisretinal or planar-locked 6-s-cis, 9-cis-retinal retained the 30 nm separation characteristic of the native pigments. This suggests that the different absorptions of the red and green pigments do not depend on different protein-induced conformations of the 6-7 carbon bond in the retinal chromophore.

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Section: Preparation Of Chromophores and Lipid Vehiclessupporting

confidence: 83%

Section: Introductionmentioning

confidence: 77%

Section: Bleaching and Regenerationmentioning

confidence: 99%

See 1 more Smart Citation

Effects of modified chromophores on the spectral sensitivity of salamander, squirrel and macaque cones.

Makino

Kraft

Mathies

et al. 1990

The Journal of Physiology

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“…Such a model, with chloride ion binding near where the polyene chain connects to the ring, is also consistent with synthetic chromophore studies of this pigment which position a negative charge near C7. 76 The simplest interpretation of the P521 data is therefore that a chloride ion bound near the ring has its binding constant affected by a relaxation which creates BSI. Since the chloride binding site is known to be composed of two positive charges, His-l96 and Lys-199 (corresponding to positions 181 and 184 in bovine rhodopsin),":" it is that area of the protein which would be affected directly by a change in the chromophore when BSI is formed.…”

Section: Batho To Lumi Processes In Other Visual Pigmentsmentioning

confidence: 99%

Spectral and Kinetic Characterization of Visual Pigment Photointermediates

Kliger

Lewis

1995

Israel Journal of Chemistry

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Abstract. The literature describing intermediates formed after photolysis of visualpigmentsis reviewed. Resultsobtainednear physiological temperatures using time-resolved optical density measurements in the UVNis region are emphasized. The general character of intermediates which appear in the course of protein function, and the role of methods with different time resolutions in their study, are discussed. Specificresults for intermediates from bathorhodopsin to metarhodopsin II are treated in detail, with limited discussion of the earlier and later species. The discussion centers on the best-understood pigment,bovine rhodopsin, but resultsfor cone-type and invertebrate pigments are also discussed. Comparison is made between the picture of the intermediates obtained using low-temperature trapping methodsand that obtainedusing kinetic measurements. The thermodynamic parameters of the intermediates are discussed, and their significance for the structure/ function of heptahelical protein intermediates in general is considered.

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“…Like rhodopsin, iodopsin contains li-cis-retinal as its chromophore. Investigations with retinal isomers and analogs suggested that iodopsin and rhodopsin have similarly shaped chromophore binding sites (6) but the point charges are in different locations (6,7).…”

mentioning

confidence: 99%

Bathoiodopsin, a primary intermediate of iodopsin at physiological temperature.

Kandori

Mizukami

Okada

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

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Measurement of the primary photochemical reaction of iodopsin, a chicken red-sensitive cone visual pigment, was carried out at room temperature by using picosecond (ps) laser photolysis. Excitation of iodopsin with a ps green pulse (pulse width, 21 ps) caused the instantaneous formation of a bathochromic product, which was stable on a ps time scale. This product may correspond to "bathoiodopsin," which was detected by low-temperature spectrophotometry. Although bathoiodopsin produced at the temperature of liquid nitrogen or helium reverted to the original pigment (iodopsin) on warming (above -170'C), the bathoiodopsin produced at physiological temperature decayed to all-trans-retinal and R-photopsin (the protein moiety of iodopsin) presumably through several intermediates. The absorption maximum of bathoiodopsin at room temperature was at 625 nm, a wavelength slightly shorter than that measured at low temperature (A4., 640 nm). The extinction coefficient of bathoiodopsin at room temperature was lower than that at low temperature and close to that of the original iodopsin at room temperature.The vertebrate retina contains two kinds of photoreceptor cells, rods and cones. A rod is a photoreceptor cell that has evolutionally acquired an extremely high photosensitivity so as to act under twilight conditions. The visual pigment in rods is called rhodopsin. Cones, however, act under daylight conditions and have a photoresponse with a wider dynamic range and a faster latency (1). Since there are at least three types of cones, each with its own distinct visual pigment possessing characteristic absorption maximum (2), integration of the photoresponses from cones generates the sensation of color in the visual cortex.The primary photoreceptive mechanism in visual transduction has been extensively investigated in rods, which contain rhodopsin as the visual pigment. Rhodopsin has an 11-cis-retinylidene chromophore attached by a protonated Schiff base linkage to a specific lysine residue of the apoprotein opsin. The primary photochemical event in rhodopsin is an isomerization around the C11=C12 bond of the 11-cisretinylidene chromophore to form photorhodopsin, a highly twisted all-trans photoproduct (3,4 (6, 7).On absorption of light, iodopsin bleaches to all-transretinal and R-photopsin (the protein moiety of iodopsin) by way of lumiiodopsin and then metaiodopsin, according to low-temperature spectrophotometry (8). Yoshizawa and Wald (9) observed that irradiation of iodopsin at the temperature of liquid nitrogen produced bathoiodopsin. Prolonged irradiation of this sample formed a steady-state photo mixture composed of iodopsin, isoiodopsin, and bathoiodopsin. This photochemical behavior of iodopsin is very similar to that of rhodopsin (Fig. 1). On warming, however, an unexpected difference between iodopsin and rhodopsin was observed; unlike bathorhodopsin, bathoiodopsin was not thermally converted to lumiiodopsin but reverted back to iodopsin above -170°C. Thus the question arises whether bathoiodopsin is a physiolo...

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Wavelength regulation in iodopsin, a cone pigment

Cited by 30 publications

References 21 publications

Effects of modified chromophores on the spectral sensitivity of salamander, squirrel and macaque cones.

Effects of modified chromophores on the spectral sensitivity of salamander, squirrel and macaque cones.

Spectral and Kinetic Characterization of Visual Pigment Photointermediates

Bathoiodopsin, a primary intermediate of iodopsin at physiological temperature.

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