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Carotenoid S1 Statein a RecombinantLight-HarvestingComplex ofPhotosystem II Tomáš Polı́vkaDonatas ZigmantasVilly Sundström2001 год

Carotenoid S1 State in a Recombinant Light-Harvesting Complex of Photosystem II
статья из журнала

Страница публикацииПубликация в OpenAlex
Аннотация: The carotenoid species lutein, violaxanthin, and zeaxanthin are crucial in the xanthophyll-dependent nonphotochemical quenching occurring in photosynthetic systems of higher plants, since they are involved in dissipation of excess energy and thus protect the photosynthetic machinery from irreversible inhibition. Nonetheless, important properties of the xanthophyll cycle carotenoids, such as the energy of their S1 electronic states, are difficult to study and were only recently determined in organic solvents [Polívka, T. (1999) Proc. Natl. Acad. Sci. U.S.A. 96, 4914. Frank, H. A. (2000) Biochemistry 39, 2831]. In the present study, we have determined the S1 energies of three carotenoid species, violaxanthin, lutein, and zeaxanthin, in their LHCII (peripheral light-harvesting complex of photosystem II) protein environment by constructing recombinant Lhcb1 (Lhc = light-harvesting complex) proteins containing single carotenoid species. Within experimental error the S1 energy is the same for all three carotenoids in the monomeric LHCII, 13900 ± 300 cm-1 (720 ± 15 nm), thus well below the Qy transitions of chlorophylls. In addition, we have found that, although the S1 lifetimes of violaxanthin, lutein, and zeaxanthin differ substantially in solution, when incorporated into the LHCII protein, their S1 states have in fact the same lifetime of about 11 ps. Despite the similar spectroscopic properties of the carotenoids bound to the LHCII, we observed a maximal fluorescence quenching when zeaxanthin was present in the LHCII complex. On the basis of these observations, we suggest that, rather than different photochemical properties of individual carotenoid species, changes in the protein conformation induced by binding of carotenoids with distinct molecular structures are involved in the quenching phenomena associated with Lhc proteins.
Год издания: 2001
Авторы: Tomáš Polı́vka, Donatas Zigmantas, Villy Sundström, Elena Formaggio, Gianfelice Cinque, Roberto Bassi
Издательство: American Chemical Society
Источник: Biochemistry
Ключевые слова: Photosynthetic Processes and Mechanisms, Plant and animal studies, Spectroscopy and Quantum Chemical Studies
Другие ссылки: Biochemistry (HTML)
PubMed (HTML)