Polarised absorption spectroscopy of chlorophyll-lipid membranes

Cherry, Richard J.; Hsu, Kwan; Chapman, D.

doi:10.1016/0005-2728(72)90179-x

Cited by 54 publications

(9 citation statements)

References 13 publications

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“…The visible linear dichroism in the rhodopsin-lipid multilayers was analyzed by following the method of analysis of linear dichroism of multilayers containing oriented chromophores developed by Cherry, Hsu and Chapman (1972) for chlorophyll-lipid membranes and by Heyn, Cherry and Muller (1977) for purple membrane multilayers. Since Cherry et aI.…”

Section: Discussionmentioning

confidence: 99%

“…(1972) have shown that the dichroism of shape of lipid bilayers is negligible, any linear dichroism detected in lipid-protein layers must arise from the nonrandom orientation of absorbing chromophores in the layers. Moreover, the treatment of Cherry et al (1972) applies only to the case where no energy transfer occurs between the chromophores. Brown (1972) has demonstrated the absence of energy transfer between rhodopsin chromophores.…”

Section: Discussionmentioning

confidence: 99%

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Linear dichroism of rhodopsin in air-water interface films

Korenbrot

Jones

1979

J. Membrain Biol.

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Air-water interface films of purified cattle rhodopsin and defined phospholipids are formed by the osmotic lysis of reconstituted membrane vesicles. The interface films thus formed consist of a phospholipid monolayer containing vesicle membrane fragments. Rhodopsin molecules at the interface are restricted within the membrane fragments where they are spectrophotometrically intact and capable of undergoing photoregeneration and chemical regeneration. Multilayers of up to 8 layers can be built from these interface films. The visible absorption band of rhodopsin in these multilayers is linearly dichroic. Quantitative analysis of the linear dichroism reveals that the dipole moment of transition of the retinal chromophore in rhodopsin forms an angle of 15 degrees +/- 4 degrees with the plane of the membrane fragments in the interface film. This orientation of the chromophore relative to the plane of the membrane is essentially the same as that observed in the intact retina. Thus, the orientation of rhodopsin in the interface films is similar to that in the intact disc membranes.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Linear dichroism of rhodopsin in air-water interface films

Korenbrot

Jones

1979

J. Membrain Biol.

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“…The most likely explanation is that a large degree of concentration quenching occurs at the higher concentration, and this reaction produces few ions. However, it cannot be completely excluded that the porphyrin has limited "solubility" in the bilayer and thus the actual bilayer concentration is not proportional to solution concentraton (Cherry et al, 1972).…”

Section: Mechanismmentioning

confidence: 99%

Kinetics of charge transfer at the lipid bilayer-water interface on the nanosecond time scale

Woodle

Zhang

Mauzerall

1987

Biophysical Journal

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Advances in instrumentation allow electrical measurements across the planar lipid bilayer to be made with nanosecond time resolution. The electron transfer reaction between photoexcited magnesium octaethylporphyrin in the lipid to a variety of ionically charged acceptors in the water is found to be purely dynamic over a wide range of concentrations of acceptors and up to the time constant of the apparatus, 4 ns. The saturation of the amplitude of the photovoltage with increasing concentration of acceptor is caused by the finite lifetime of the excited state, not by formation of a static pigment-acceptor complex. The reactions are an excellent probe of the lipid-water interface over an extended time scale. No appreciable barrier to reaction exists at this interface beyond the 5-ns time. That is, any water or choline group structure may be evanescent on this time scale. Electrostatic interactions indicate that the acceptor molecules penetrate to the level of the phosphocholine groups with differing orientations. It will be possible to extend the time scale into the picosecond range by decreasing the response time and by deconvolutions.

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“…The angle between the transition moment of the chromophore and the plane of the membrane can be derived from the measured dichroic ratio. The dichroic ratio for chromophores randomly oriented about the normal to the plane of the membrane is given by [18]: D = sin20 + 2 tan2 9 cos20…”

Section: Linear Dichroism Of Bacteriorhodopsinmentioning

confidence: 99%