紫黄质
光防护
光系统I
生物
生物物理学
光系统II
光合作用
结晶学
化学
植物
叶黄素
玉米黄质
类胡萝卜素
作者
Zhenhua Li,Cuicui Zhou,Songhao Zhao,Jinyang Zhang,Xueyang Liu,Miao Sang,Xiaochun Qin,Yanyan Yang,Guangye Han,Tingyun Kuang,Jian-Ren Shen,Wenda Wang
标识
DOI:10.1016/j.str.2023.08.001
摘要
Light-harvesting complexes of photosystem II (LHCIIs) in green algae and plants are vital antenna apparatus for light harvesting, energy transfer, and photoprotection. Here we determined the structure of a siphonous-type LHCII trimer from the intertidal green alga Bryopsis corticulans by X-ray crystallography and cryo-electron microscopy (cryo-EM), and analyzed its functional properties by spectral analysis. The Bryopsis LHCII (Bry-LHCII) structures in both homotrimeric and heterotrimeric form show that green light-absorbing siphonaxanthin and siphonein occupied the sites of lutein and violaxanthin in plant LHCII, and two extra chlorophylls (Chls) b replaced Chls a. Binding of these pigments expands the blue-green light absorption of B. corticulans in the tidal zone. We observed differences between the Bry-LHCII homotrimer crystal and cryo-EM structures, and also between Bry-LHCII homotrimer and heterotrimer cryo-EM structures. These conformational changes may reflect the flexibility of Bry-LHCII, which may be required to adapt to light fluctuations from tidal rhythms.
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