Primary Citation Related Structures: 9JZR, 9K1E, 9K7V
PubMed Abstract:
The light-harvesting complexes of photosystem I (PSI) and PSII (LHCI and LHCII) in Bryopsis corticulans (B. corticulans) are homologous to those in Chlamydomonas reinhardtii and land plants but exhibit a distinct chlorophyll (Chl) and carotenoid composition. Here, we report cryo-electron microscopy structures of the PSI-LHCI 10 -LHCII 9 supercomplex, comprising three LHCII trimers, and the C 2 S 2 M 2 N 2 -type PSII-LHCII supercomplex from B. corticulans. In the PSI supercomplex, ten LHCI subunits assemble into two belts and one heterodimer, coordinating a total of 86 Chl a and 65 Chl b molecules (Chl a/b ratio of 1.3, compared with 3.4 in C. reinhardtii), as well as 18 siphonaxanthin, 2 siphonein, and 13 α-carotene molecules. Of the three LHCII trimers bound to the PSI-LHCI supercomplex, two are anchored to the PSI core primarily via phosphorylated subunits, whereas the third, non-phosphorylated trimer is stabilized through interactions with Lhca-d and the adjacent LHCII trimer. In the C 2 S 2 M 2 N 2 -type PSII-LHCII supercomplex, the N-LHCII is positioned closer to the PSII core than in C. reinhardtii, likely owing to loss of the linker motif in the N-terminal region of B. corticulans CP29. Structure-based energy transfer analysis suggests that this spatial rearrangement enhances the efficiency of excitation energy transfer from N-LHCII to the PSII core. Collectively, these findings reveal structural adaptations that underlie the acclimation strategies of siphonous green algae inhabiting intertidal environments.
Organizational Affiliation:
State Key Laboratory of Forage Breeding-by-Design and Utilization, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of the Chinese Academy of Sciences, Yuquan Rd, Shijingshan District, Beijing 100049, China.
State Key Laboratory of Forage Breeding-by-Design and Utilization, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; China National Botanical Garden, Beijing 100093, China.
CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
State Key Laboratory of Forage Breeding-by-Design and Utilization, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of the Chinese Academy of Sciences, Yuquan Rd, Shijingshan District, Beijing 100049, China; China National Botanical Garden, Beijing 100093, China; Academician Workstation of Agricultural High-Tech Industrial Area of the Yellow River Delta, National Center of Technology Innovation for Comprehensive Utilization of Saline-Alkali Land, Dongying 257300, China.
State Key Laboratory of Forage Breeding-by-Design and Utilization, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; China National Botanical Garden, Beijing 100093, China; Academician Workstation of Agricultural High-Tech Industrial Area of the Yellow River Delta, National Center of Technology Innovation for Comprehensive Utilization of Saline-Alkali Land, Dongying 257300, China.
State Key Laboratory of Forage Breeding-by-Design and Utilization, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of the Chinese Academy of Sciences, Yuquan Rd, Shijingshan District, Beijing 100049, China; China National Botanical Garden, Beijing 100093, China; Academician Workstation of Agricultural High-Tech Industrial Area of the Yellow River Delta, National Center of Technology Innovation for Comprehensive Utilization of Saline-Alkali Land, Dongying 257300, China. Electronic address: liucheng@ibcas.ac.cn.
State Key Laboratory of Forage Breeding-by-Design and Utilization, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; China National Botanical Garden, Beijing 100093, China; Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, 700-8530 Okayama, Japan. Electronic address: shen@cc.okayama-u.ac.jp.
State Key Laboratory of Forage Breeding-by-Design and Utilization, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of the Chinese Academy of Sciences, Yuquan Rd, Shijingshan District, Beijing 100049, China; China National Botanical Garden, Beijing 100093, China; Academician Workstation of Agricultural High-Tech Industrial Area of the Yellow River Delta, National Center of Technology Innovation for Comprehensive Utilization of Saline-Alkali Land, Dongying 257300, China. Electronic address: wdwang@ibcas.ac.cn.
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