Control Mechanism of Excitation Energy Transfer in a Complex Consisting of Photosystem II and Fucoxanthin Chlorophyll a/c-Binding Protein
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- 作者：Ryo Nagao ; Makio Yokono ; Tatsuya Tomo ; Seiji Akimoto
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2014
- 出版时间：September 4, 2014
- 年：2014
- 卷：5
- 期：17
- 页码：2983-2987
- 全文大小：254K
- ISSN：1948-7185
文摘
Fucoxanthin chlorophyll (Chl) a/c-binding protein (FCP) is a unique light-harvesting antenna in diatoms, which are photosynthesizing algae ubiquitous in aquatic environments. However, it is unknown how excitation energy is trapped and quenched in a complex consisting of photosystem II and FCP (PSII鈥揊CPII complex). Here, we report the control mechanism of excitation energy transfer in the PSII鈥揊CPII complexes isolated from a diatom, Chaetoceros gracilis, as revealed by picosecond time-resolved fluorescence spectroscopy. The results showed that Chl-excitation energy is harvested in low-energy Chls near/within FCPII under the 77 K conditions, whereas most of the energy is trapped in reaction center Chls in PSII under the 283 K conditions. Surprisingly, excitation energy quenching was observed in a part of PSII鈥揊CPII complexes with the time constants of hundreds of picosecond, thus indicating the large contribution of FCPII to energy trapping and quenching. On the basis of these results, we discuss the light-harvesting strategy of diatoms.