Photoprotection in a purple phototrophic bacterium mediated by oxygen-dependent alteration of carotenoid excited-state properties

0377720 - BC 2013 RIV US eng J - Článek v odborném periodiku
Šlouf, V. - Chábera, P. - Olsen, J.D. - Martin, E.C. - Qian, P. - Hunter, C.N. - Polívka, Tomáš
Photoprotection in a purple phototrophic bacterium mediated by oxygen-dependent alteration of carotenoid excited-state properties.
Proceedings of the National Academy of Sciences of the United States of America. Roč. 109, č. 22 (2012), s. 8570-8575. ISSN 0027-8424. E-ISSN 1091-6490
Výzkumný záměr: CEZ:AV0Z50510513
Klíčová slova: charge-transfer state * photoprotection * purple bacteria * photosynthesis
Kód oboru RIV: BO - Biofyzika
Impakt faktor: 9.737, rok: 2012

We performed ultrafast absorption spectroscopy on membranes containing reaction center-light-harvesting 1-PufX (RC-LH1-PufX) complexes and show that when oxygen is present the incorporation of the keto group into spheroidene, forming spheroidenone, reconfigures the energy transfer pathway in the LH1, but not the LH2, antenna. The spheroidene/spheroidenone transition acts as a molecular switch, which is suggested to twist spheroidenone into an s-trans configuration, increasing its conjugation length and lowering the energy of the lowest triplet state so it can act as an effective quencher of singlet oxygen. We propose that spheroidene/spheroidenone switching represents a simple and effective photoprotective mechanism, of likely importance for phototrophic bacteria that encounter both light and oxygen.
Trvalý link: http://hdl.handle.net/11104/0209812