Carotenoids in plant photoprotection

Schrott, E. L.

doi:10.1351/pac198557050729

Cited by 13 publications

(3 citation statements)

References 11 publications

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“…They contribute to light harvesting by their strong absorption in the visible part of the spectrum that originates from a long conjugated chain of double bonds. In addition, carotenoids play a very important role in photoprotection (Foote and Denny, 1968;Schrott, 1985;Frank et al, 1991). These two functions have been studied extensively in the lightharvesting 2 complexes (LH2) of purple bacteria: through their singlet states, carotenoids capture the sunlight in the blue-green part of the spectrum, and transfer 25-95% of it to B800 and/or B850 bacteriochlorophyll (BChl) a chromophores (Kramer et al, 1984;Chadwick et al, 1987;Mimuro and Katoh, 1991;Andersson et al, 1996;Scholes et al, 1997); through their triplet states, they quench the BChl excited triplet states which-if long-lived-would lead to formation of singlet oxygen and subsequently to damage of the complex (Nilsson et al, 1972;Cogdell and Frank, 1987).…”

Section: Introductionmentioning

confidence: 99%

Circular Dichroism of Carotenoids in Bacterial Light-Harvesting Complexes: Experiments and Modeling

Georgakopoulou

Grondelle

Zwan

2004

Biophysical Journal

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In this work we investigate the origin and characteristics of the circular dichroism (CD) spectrum of rhodopin glucoside and lycopene in the light-harvesting 2 complex of Rhodopseudomonas acidophila and Rhodospirillum molischianum, respectively. We successfully model their absorption and CD spectra based on the high-resolution structures. We assume that these spectra originate from seven interacting transition dipole moments: the first corresponds to the 0-0 transition of the carotenoid, whereas the remaining six represent higher vibronic components of the S2 state. From the absorption spectra we get an estimate of the Franck-Condon factors of these transitions. Furthermore, we investigate the broadening mechanisms that lead to the final shape of the spectra and get an insight into the interaction energy between carotenoids. Finally, we examine the consequences of rotations of the carotenoid transition dipole moment and of deformations in the light-harvesting 2 complex rings. Comparison of the modeled carotenoid spectra with modeled spectra of the bacteriochlorophyll QY region leads to a refinement of the modeling procedure and an improvement of all calculated results. We therefore propose that the combined carotenoid and bacteriochlorophyll CD can be used as an accurate reflection of the overall structure of the light-harvesting complexes.

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Section: Introductionmentioning

confidence: 99%

Circular Dichroism of Carotenoids in Bacterial Light-Harvesting Complexes: Experiments and Modeling

Georgakopoulou

Grondelle

Zwan

2004

Biophysical Journal

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“…Carotenoids are a form of linear polyenes which occur naturally in photosynthetic organisms. They function as light-harvesting molecules and as protectors against harmful photooxidation reactions (Schrott, 1985). They absorb light in a wavelength region where the chlorophyllous pigments have a gap in their absorption spectrum, and their excitation energy is normally efficiently transferred to chlorophylls or bacteriochlorophylls (Siefermann-Harms, 1985).…”

Section: Introductionmentioning

confidence: 99%

Absorption Spectral Shifts of Carotenoids Related to Medium Polarizability

Andersson

Gillbro

Ferguson

et al. 1991

Photochem & Photobiology

175

132

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Abstract–Solvent induced absorption spectral shifts of the electronic transition from ground 1 Ag state to the excited 1Bu state in carotenoids have been studied. It is shown that the shift depends only on dispersion interactions in non‐polar solvents. In polar media there is just a small extra contribution to the red‐shift, due to other forms of interactions. The spectral shifts are well described by the theory, which expresses the shift relative to the gas phase value, as a function of solvent polarizability. The main conclusion is that the dominating mechanism behind the large red‐shifted absorbance of carotenoids in the proteinacous environment, in vivo, is the mutual polarizability interactions between the carotenoids and the surrounding medium. The solution‐phase values of the dipole moments of the lAg to 1Bu transitions and the differences of isotropic polarizability between 1Bu and lAg states of carotenoids in non‐polar solvents are calculated and found to be around 13 D and 360 Å3 respectively. From the great overlap of absorption spectra between carotenoids in quinoline and carotenoids in vivo in purple bacterial antenna complexes, it can be expected that the carotenoids are surrounded by several aromatic amino acids in vivo. Comparisons have been done between the exicted states in carotenoids and in linear conjugated polyenes.

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“…Moreover, as carotenoidproducing microorganisms, various kinds of species including a photosynthetic bacterium have been studied. Research on the physiological function of carotenoid is advanced; it has been elucidated that a chlorophyll molecule and protein form a complex, which becomes an antenna pigment, and has a condensing action, or it has a protective action against film destruction by light [2][3][4][5][6][7][8][9] . The surface of the sea and coral reefs in subtropical regions are severe environments for the growth of microorganisms because reactive oxygen species are generated by intense irradiation with strong sunlight.…”

Section: Introductionmentioning

confidence: 99%

Culture Characteristics of Carotenoid-producing Filamentous Fungus T-1, and Carotenoid Production

et al. 2007

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The culture characteristics, carotenoid production, and associated biosynthetic pathway of strain T-1 were examined. As a result of examining the culture temperature and light irradiation, an increase of neurosporaxanthin and neurosporaxanthin b-D-glucopyranoside was observed at a low temperature and 0 lx. It was suggested that highly polar carotenoids, such as neurosporaxanthin, and carotenoid glycosides were involved in the stabilization of membrane during nutrition storage other than the defense function of fungus bodies. Strain T-1 produced lycopene, b-carotene, g-carotene, torulene, neurosporaxanthin, and neurosporaxanthin b-D-glucopyranoside, as assessed by HPLC, LC-MS, and NMR analysis. Carotenoid biosynthesis begins with neurosporene, passing to lycopene and g-carotene through cyclization, and produces b-carotene. In addition, it is saturated, g-carotene is converted to torulene, and neurosporaxanthin is produced. Thus, the carotenoid biosynthetic pathway in strain T-1 was estimated.

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Carotenoids in plant photoprotection

Abstract: -One of the roles of carotenoids in plants which are proposed is to serve as protecting agents against deleterious effects of light.

Cited by 13 publications

References 11 publications

Circular Dichroism of Carotenoids in Bacterial Light-Harvesting Complexes: Experiments and Modeling

Circular Dichroism of Carotenoids in Bacterial Light-Harvesting Complexes: Experiments and Modeling

Absorption Spectral Shifts of Carotenoids Related to Medium Polarizability

Culture Characteristics of Carotenoid-producing Filamentous Fungus T-1, and Carotenoid Production

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