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Publication Abstract from PubMed

Light-harvesting complexes (LHCs) are diversified among photosynthetic organisms, and the structure of the photosystem I-LHC (PSI-LHCI) supercomplex has been shown to be variable depending on the species of organisms. However, the structural and evolutionary correlations of red-lineage LHCs are unknown. Here, we determined a 1.92-A resolution cryoelectron microscopic structure of a PSI-LHCI supercomplex isolated from the red alga Cyanidium caldarium RK-1 (NIES-2137), which is an important taxon in the Cyanidiophyceae. We subsequently investigated the correlations of PSI-LHCIs from different organisms through structural comparisons and phylogenetic analysis. The PSI-LHCI structure obtained shows five LHCI subunits surrounding a PSI-monomer core. The five LHCIs are composed of two Lhcr1s, two Lhcr2s, and one Lhcr3. Phylogenetic analysis of LHCs bound to PSI in the red-lineage algae showed clear orthology of LHCs between C. caldarium and Cyanidioschyzon merolae, whereas no orthologous relationships were found between C. caldarium Lhcr1-3 and LHCs in other red-lineage PSI-LHCI structures. These findings provide evolutionary insights into conservation and diversity of red-lineage LHCs associated with PSI.

The structure of PSI-LHCI from Cyanidium caldarium provides evolutionary insights into conservation and diversity of red-lineage LHCs.,Kato K, Hamaguchi T, Kumazawa M, Nakajima Y, Ifuku K, Hirooka S, Hirose Y, Miyagishima SY, Suzuki T, Kawakami K, Dohmae N, Yonekura K, Shen JR, Nagao R Proc Natl Acad Sci U S A. 2024 Mar 12;121(11):e2319658121. doi: , 10.1073/pnas.2319658121. Epub 2024 Mar 5. PMID:38442179^[1]

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