Stark fluorescence spectroscopy reveals two emitting sites in the dissipative state of FCP antennas

• Published in: Biochimica et biophysica acta 2014-01, Vol.1837 (1), p.193-200
• Main Authors: Wahadoszamen, Md, Ghazaryan, Artur, Cingil, Hande E., Ara, Anjue Mane, Büchel, Claudia, van Grondelle, Rienk, Berera, Rudi
• Format: Article
• Language: English
• Subjects: Charge transfer states; Chlorophyll Binding Proteins - chemistry; Diatoms; Diatoms - chemistry; Diatoms - physiology; Energy dissipation; Energy Metabolism; Light; Light harvesting antenna; Light-Harvesting Protein Complexes - chemistry; Nonphotochemical quenching; Photosynthesis; Spectrometry, Fluorescence; Stark spectroscopy; Xanthophylls - chemistry
• ISSN: 0005-2728; 0006-3002; 1879-2650
• DOI: 10.1016/j.bbabio.2013.09.001

Diatoms are characterized by very efficient photoprotective mechanisms where the excess energy is dissipated as heat in the main antenna system constituted by fucoxanthin–chlorophyll (Chl) protein complexes (FCPs). We performed Stark fluorescence spectroscopy on FCPs in their light-harvesting and energy dissipating states. Our results show that two distinct emitting bands are created upon induction of energy dissipation in FCPa and possibly in FCPb. More specifically one band is characterized by broad red shifted emission above 700nm and bears strong similarity with a red shifted band that we detected in the dissipative state of the major light-harvesting complex II (LHCII) of plants [26]. We discuss the results in the light of different mechanisms proposed to be responsible for photosynthetic photoprotection. •We identified two emitting species in quenched FCP by Stark fluorescence spectroscopy.•The two species show very different excited state electronic structure and dynamics.•We propose that the two species originate from Chl–Chl and Chl–Car interactions.