β‑Carotene Probes the Energy Transfer Pathway in the Photosystem II Core Complex
journal contributionposted on 28.05.2019, 00:00 by Yusuke Yoneda, Yutaka Nagasawa, Yasufumi Umena, Hiroshi Miyasaka
The dynamics of the intact photosystem II core complex (PSII-CC) has been investigated extensively to elucidate its excellent photofunction. However, it is significantly difficult to observe the primary photosynthetic processes in PSII-CC because a vast number of chlorophylls (Chl) in the core complex show similar spectral features. In the present work, the dynamics of the energy transfer (ET) from β-carotene (Bcr) in intact PSII-CC followed by charge separation (CS) at the reaction center (RC) with different excitation wavelengths were compared. Upon excitation at 510 nm, which selectively excites Bcr (Bcr651) inside of the D1-D2 RC, the pheophytin anion absorption band appeared within 9.6 ps. On the other hand, upon excitation at 490 nm, mainly exciting unspecified Bcr in the antenna complex, the anion band appeared after 20 ps. These excitation wavelength dependence experiments revealed a new ET pathway of PSII-CC, which indicates that the initial CS of PSII-CC is limited by ET to the RC.
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anion banddynamic490 nmET pathway9.6 psenergy transferexcitation wavelengthsD 1-D RCβ- carotenePSII-CCpheophytin anion absorption bandCSBcrEnergy Transfer Pathwayphotosynthetic processes510 nmcharge separationPhotosystem II Core Complexphotosystem II core20 psexcitation wavelength dependence experimentsreaction center