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Publication Abstract from PubMed

In oxygenic photosynthetic organisms, light energy is captured by antenna systems and transferred to photosystem II (PSII) and photosystem I (PSI) to drive photosynthesis(1,2). The antenna systems of red algae consist of soluble phycobilisomes (PBSs) and transmembrane light-harvesting complexes (LHCs)(3). Excitation energy transfer pathways from PBS to photosystems remain unclear owing to the lack of structural information. Here we present in situ structures of PBS-PSII-PSI-LHC megacomplexes from the red alga Porphyridium purpureum at near-atomic resolution using cryogenic electron tomography and in situ single-particle analysis(4), providing interaction details between PBS, PSII and PSI. The structures reveal several unidentified and incomplete proteins and their roles in the assembly of the megacomplex, as well as a huge and sophisticated pigment network. This work provides a solid structural basis for unravelling the mechanisms of PBS-PSII-PSI-LHC megacomplex assembly, efficient energy transfer from PBS to the two photosystems, and regulation of energy distribution between PSII and PSI.

In situ structure of the red algal phycobilisome-PSII-PSI-LHC megacomplex.,You X, Zhang X, Cheng J, Xiao Y, Ma J, Sun S, Zhang X, Wang HW, Sui SF Nature. 2023 Apr;616(7955):199-206. doi: 10.1038/s41586-023-05831-0. Epub 2023 , Mar 15. PMID:36922595^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.