Li Dan-Hong, Wang Wenda, Zhou Cuicui, Zhang Yan, Zhao Songhao, Zhou Yi-Ming, Gao Rong-Yao, Yao Hai-Dan, Fu Li-Min, Wang Peng, Shen Jian-Ren, Kuang Tingyun, Zhang Jian-Ping
Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing 100872, China.
School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
iScience. 2022 Dec 7;26(1):105761. doi: 10.1016/j.isci.2022.105761. eCollection 2023 Jan 20.
The light-harvesting complex II of (-LHCII), a green alga, differs from that of spinach (-LHCII) in chlorophyll (Chl) and carotenoid (Car) compositions. We investigated ultrafast excitation dynamics of -LHCII with visible-to-near infrared time-resolved absorption spectroscopy. Absolute fluorescence quantum yield ( ) of LHCII and spectroelectrochemical (SEC) spectra of Chl and were measured to assist the spectral analysis. Red-light excitation at Chl Q-band, but not Car-band, induced transient features resembling the characteristic SEC spectra of Chl and Chl , indicating ultrafast photogeneration of Chl-Chl charge transfer (CT) species; and Car declined whereas CT species increased upon prolonging excitation wavelength, showing positive correlation of Chl deactivation with Chl-Chl CT formation. Moreover, ultrafast Chl -to-Chl and Car-to-Chl singlet excitation transfer were illustrated. The red-light induction of Chl-Chl CT species, as also observed for -LHCII, is considered a general occurrence for LHCIIs in light-harvesting form.
绿藻的捕光复合物II（-LHCII）在叶绿素（Chl）和类胡萝卜素（Car）组成上与菠菜的捕光复合物II（-LHCII）不同。我们用可见-近红外时间分辨吸收光谱研究了-LHCII的超快激发动力学。测量了LHCII的绝对荧光量子产率（）以及Chl和的光谱电化学（SEC）光谱以辅助光谱分析。在Chl Q带而非Car带的红光激发诱导出类似于Chl和Chl特征SEC光谱的瞬态特征，表明Chl-Chl电荷转移（CT）物种的超快光生；随着激发波长延长，和Car下降而CT物种增加，表明Chl失活与Chl-Chl CT形成呈正相关。此外，还阐明了从Chl到Chl以及从Car到Chl的超快单重态激发转移。Chl-Chl CT物种的红光诱导现象，在-LHCII中也有观察到，被认为是处于捕光形式的LHCII的普遍现象。
