Twisting a Beta-Carotene, an Adaptive Trick from Nature for Dissipating Energy during Photoprotection

0473562 - MBÚ 2018 RIV US eng J - Článek v odborném periodiku
Manuel J. Llansola-Portoles, M.J. - Sobotka, Roman - Kish, E. - Shukla, M.K. - Pascal, A.A. - Polívka, T. - Robert, B.
Twisting a Beta-Carotene, an Adaptive Trick from Nature for Dissipating Energy during Photoprotection.
Journal of Biological Chemistry. Roč. 292, č. 4 (2017), s. 1396-1403. ISSN 0021-9258. E-ISSN 1083-351X
Grant CEP: GA ČR GBP501/12/G055; GA ČR(CZ) GA14-13967S
Institucionální podpora: RVO:61388971
Klíčová slova: LIGHT-HARVESTING COMPLEX * RESONANCE RAMAN-SPECTRA * PHOTOSYSTEM-II
Obor OECD: Microbiology
Impakt faktor: 4.011, rok: 2017

Cyanobacteria possess a family of one-helix high light-inducible proteins (Hlips) that are homologous to light-harvesting antenna of plants and algae. An Hlip protein, high light-inducible protein D (HliD) purified as a small complex with the Ycf39 protein is evaluated using resonance Raman spectroscopy. We show that the HliD binds two different beta-carotenes, each present in two non-equivalent binding pockets with different conformations, having their (0,0) absorption maxima at 489 and 522 nm, respectively. Both populations of beta-carotene molecules were in all-trans configuration and the absorption position of the farthest blue-shifted beta-carotene was attributed entirely to the polarizability of the environment in its binding pocket. In contrast, the absorption maximum of the red-shifted beta-carotene was attributed to two different factors: the polarizability of the environment in its binding pocket and, more importantly, to the conformation of its beta-rings. This second beta-carotene has highly twisted beta-rings adopting a flat conformation, which implies that the effective conjugation length N is extended up to 10.5 modifying the energetic levels. This increase in N will also result in a lower S-1 energy state, which may provide a permanent energy dissipation channel. Analysis of the carbonyl stretching region for chlorophyll a excitations indicates that the HliD binds six chlorophyll a molecules in five non-equivalent binding sites, with at least one chlorophyll a presenting a slight distortion to its macrocycle. The binding modes and conformations of HliD-bound pigments are discussed with respect to the known structures of LHCII and CP29.
Trvalý link: http://hdl.handle.net/11104/0270697