Properties of Rhodopsin Dependent on Associated Phospholipid

Zorn, Mark; Futterman, Sidney

doi:10.1016/s0021-9258(18)62407-x

Cited by 100 publications

(11 citation statements)

References 20 publications

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“…The spectra were recorded at 20°. (Zorn and Futterman, 1971). The usual criterion of purity is the ratio of absorbance at 278 nm to that at 498 nm, the lowest spectral ratio corresponding to the purest preparation, The lowest ratios reported in the literature for rhodopsin purified in different ways lie in the range 1.6-1.8.…”

Section: Discussionmentioning

confidence: 99%

“…Two recent reports in the literature have dealt with the subject of phospholipid requirements for rhodopsin regenerability. Zorn and Futterman (1971) have reported that partially delipidated cattle rhodopsin is not regenerable, and of a variety of phospholipids examined, only phosphatidylethanolamine appeared to be capable of restoring the regenerability of the bleached pigment. Shichi (1971) has reported that the photochemical regenerability of rhodopsin is lost when 20-30 % of the phospholipid is extracted from cattle rod outer segment membranes, but is restored upon the addition of phospholipid.…”

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confidence: 97%

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Lipid requirements for rhodopsin regenerability

Hong¹,

Hubbell²

1973

Biochemistry

254

121

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 97%

Lipid requirements for rhodopsin regenerability

Hong¹,

Hubbell²

1973

Biochemistry

254

121

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“…There are a number of physical or chemical properties of disc membranes which change upon illumination. Among these are the visible absorption spectrum of rhodopsin (Wald, 1968), low angle X-ray scattering (Blasie, 1972), exposure of sulfhydryl groups (Wald and Brown, 1952;Zorn and Futterman, 1971), accessibility of the Schiff base linkage of retinal to reducing agents (Bownds and Wald, 1965;Fager et al, 1972), accessibility of ionizable groups (Radding and Wald, 1955;Ostroy, 1974), and the availability of hydroxyl (serine) groups of rhodopsin as substrates for a protein kinase (Kuhn et al, 1973;Bownds et al, 1972). Most or all of these changes can be considered as direct manifestations of the photoisomerization of retinal or associated changes in the conformation of opsin, since in quantitative terms the properties in question change on a molecule per molecule basis as rhodopsin is bleached.…”

Section: Discussionmentioning

confidence: 99%

Link between rhodopsin and disk membrane cyclic nucleotide phosphodiesterase. Action spectrum and sensitivity to illumination

Keirns¹,

Miki²,

Bitensky³

et al. 1975

Biochemistry

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Frog (Rana pipiens) rod outer segment disc membranes contain guanosine 3',5'-cyclic monophosphate phosphodiesterase (EC 3.1.4.1.c) which, in the presence of ATP, is stimulated 5- to 20-fold by illumination. The effectiveness of monochromatic light of different wavelengths in activating phosphodiesterase was examined. The action spectrum has a maximum of 500 nm, and the entire spectrum from 350 to 800 nm closely matches the absorption spectrum of rhodopsin, which is apparently the pigment which mediates the effects of light on phosphodiesterase activity. trans-Retinal alone does not mimic light. Half-maximal activation of the phosphodiesterase occurs with a light exposure which bleaches 1/2000 of the rhodopsins. Half-maximal activation can also be achieved by mixing 1 part of illuminated disc membranes in which the rhodopsin is bleached with 99 parts of unilluminated membranes. Regeneration of bleached rhodopsin by addition of 11-cis-retinal is illuminated disc membranes reverses the ability of these membranes to activate phosphodiesterase in unilluminated membranes. If the rhodopsin regenerated by 11-cis-retinal is illuminated again, it regains the ability to activate phosphodiesterase. These studies show that the levels of cyclic nucleotides in vetebrate rod outer segments are regulated by minute amounts of light and clearly indicate that rhodopsin is the photopigment whose state of illumination is closely linked to the enzymatic activity of disc membrane phosphodiesterase.

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“…The phospholipid headgroups are 90% positively charged in the ROS membranes and are expected to make extensive contacts with negatively charged O-H groups of the water and/or contacts with rhodopsin amino acid side chains which may provide necessary structural stability to ROS membranes. The lipid hydrocarbon chains are directed toward the hydrophobic core of the rhodopsin located on seven helices spanning the membrane bilayer (Zorn & Futterman, 1971), and large hydrophobic interactions are expected which may play a dominant role in stabilizing the rhodopsin-lipid membrane-matrix.…”

Section: Resultsmentioning

confidence: 99%

Fourier Transform Infrared Study of the Rod Outer Segment Disk and Plasma Membranes of Vertebrate Retina

Lamba

Borchman²,

O’Brien³

1994

Biochemistry

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Phospholipid composition and structure of disk and plasma membranes purified from bovine rod outer segments (ROS) are examined using Fourier transform infrared spectroscopy. Vibrational data indicate that both disk and plasma membranes lack sphingophospholipids, in contrast to the lens membranes. The hydrocarbon chains of the disk lipids are unsaturated by a factor of 5 over the acyl chains of the plasma lipids. The plasma lipids with 3-fold higher cholesterol and 5-fold higher saturation melt at a higher temperature (26 degrees C) than the disk lipids which melt at 16 degrees C. The transition temperature decreases by more than 20 degrees C in going from disk lipids to disk membrane, indicating a large drop in the enthalpy of the ROS membrane-matrix, presumably due to enhanced rhodopsin-lipid interaction. The lipid composition predisposes the disk and plasma membranes to be fluid and structurally disordered (about 84%) around physiological temperature. The fluid phospholipid environment of the disk membrane (i.e., just a few degrees above subzero temperatures) is considered to be vital for the ROS photoreceptor function. The amide I band profile of rhodopsin indicates an extensive alpha-helical (53%) peptide chain, with little beta-sheet (21%) and beta-turns (18%) in ROS membranes. This structure and/or conformation is conserved between 0-60 degrees C even though disk and plasma lipids undergo a phase change. The H-D exchange data indicate that as much as 84% of the peptide residues of ROS membranes in partially bleached retinas is accessible to D2O solvent after 1 h.(ABSTRACT TRUNCATED AT 250 WORDS)

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Properties of Rhodopsin Dependent on Associated Phospholipid

Cited by 100 publications

References 20 publications

Lipid requirements for rhodopsin regenerability

Lipid requirements for rhodopsin regenerability

Link between rhodopsin and disk membrane cyclic nucleotide phosphodiesterase. Action spectrum and sensitivity to illumination

Fourier Transform Infrared Study of the Rod Outer Segment Disk and Plasma Membranes of Vertebrate Retina

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