Photoinduced chlorophyll charge transfer state identified in the light-harvesting complex II from a marine green alga Bryopsis corticulans

Dan-Hong Li; Wenda Wang; Cuicui Zhou; Yan Zhang; Songhao Zhao; Yi-Ming Zhou; Rong-Yao Gao; Hai-Dan Yao; Li-Min Fu; Peng Wang; Jian-Ren Shen; Tingyun Kuang; Jian-Ping Zhang

doi:10.1016/j.isci.2022.105761

Photoinduced chlorophyll charge transfer state identified in the light-harvesting complex II from a marine green alga Bryopsis corticulans

iScience. 2022 Dec 7;26(1):105761. doi: 10.1016/j.isci.2022.105761. eCollection 2023 Jan 20.

Authors

Dan-Hong Li^{1

2}, Wenda Wang³, Cuicui Zhou³, Yan Zhang¹, Songhao Zhao³, Yi-Ming Zhou¹, Rong-Yao Gao¹, Hai-Dan Yao¹, Li-Min Fu¹, Peng Wang¹, Jian-Ren Shen^{3

4}, Tingyun Kuang³, Jian-Ping Zhang¹

Affiliations

¹ Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing 100872, China.
² School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
³ Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
⁴ Research Institute for Interdisciplinary Science, and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.

Abstract

The light-harvesting complex II of Bryopsis corticulans (B-LHCII), a green alga, differs from that of spinach (S-LHCII) in chlorophyll (Chl) and carotenoid (Car) compositions. We investigated ultrafast excitation dynamics of B-LHCII with visible-to-near infrared time-resolved absorption spectroscopy. Absolute fluorescence quantum yield (Φ _FL) of LHCII and spectroelectrochemical (SEC) spectra of Chl a and b were measured to assist the spectral analysis. Red-light excitation at Chl Q_y-band, but not Car-band, induced transient features resembling the characteristic SEC spectra of Chl a ^⋅+ and Chl b ^⋅-, indicating ultrafast photogeneration of Chl-Chl charge transfer (CT) species; Φ _FL and ³Car^∗ declined whereas CT species increased upon prolonging excitation wavelength, showing positive correlation of ¹Chl^∗ deactivation with Chl-Chl CT formation. Moreover, ultrafast Chl b-to-Chl a and Car-to-Chl singlet excitation transfer were illustrated. The red-light induction of Chl-Chl CT species, as also observed for S-LHCII, is considered a general occurrence for LHCIIs in light-harvesting form.

Keywords: biodevices; environmental chemical engineering; green chemistry.