Molecular origin of photoprotection in cyanobacteria probed by watermarked femtosecond stimulated Raman spectroscopy

0501677 - FZÚ 2019 RIV US eng J - Článek v odborném periodiku
Hontani, Y. - Kloz, Miroslav - Polívka, T. - Shukla, Mahendra K. - Sobotka, Roman - Kennis, J.T.M.
Molecular origin of photoprotection in cyanobacteria probed by watermarked femtosecond stimulated Raman spectroscopy.
Journal of Physical Chemistry Letters. Roč. 9, č. 7 (2018), s. 1788-1792. ISSN 1948-7185
Grant CEP: GA ČR GA17-01137S; GA ČR(CZ) GA17-08755S; GA ČR(CZ) GBP501/12/G055; GA MŠMT(CZ) LO1416
Institucionální podpora: RVO:68378271 ; RVO:61388971
Klíčová slova: light-harvesting complex * charge-transfer state * energy-dissipation * beta-carotene * transient absorption * internal-conversion * excited-states * protein * photosynthesis * mechanism
Obor OECD: Fluids and plasma physics (including surface physics); Microbiology (MBU-M)
Impakt faktor: 7.329, rok: 2018

Photoprotection is fundamental in photosynthesis to avoid oxidative photodamage upon excess light exposure. Excited chlorophylls (Chl) are quenched by carotenoids, but the precise molecular origin remains controversial. The cyanobacterial HliC protein belongs to the Hlip family ancestral to plant light-harvesting complexes, and binds Chl a and beta-carotene in 2:1 ratio. We analyzed HliC by watermarked femtosecond stimulated Raman spectroscopy to follow the time evolution of its vibrational modes. We observed a 2 ps rise of the C=C stretch band of the 2A(g)(-) (S-1) state of beta- carotene upon CM a excitation, demonstrating energy transfer quenching and fast excess-energy dissipation. We detected two distinct beta-carotene conformers by the C=C stretch frequency of the 2A(g)(-) (S-1) state, but only the beta-carotene whose 2A(g)(-) energy level is significantly lowered and has a lower C=C stretch frequency is involved in quenching. channel.

Trvalý link: http://hdl.handle.net/11104/0293667