RRC ID 78635
Author 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.
Title The structure of PSI-LHCI from Cyanidium caldarium provides evolutionary insights into conservation and diversity of red-lineage LHCs.
Journal Proc Natl Acad Sci U S A
Abstract 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-Å 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.
Volume 121(11)
Pages e2319658121
Published 2024-3-12
DOI 10.1073/pnas.2319658121
PMID 38442179
PMC PMC10945839
MeSH Biological Evolution Cryoelectron Microscopy Photosystem I Protein Complex* / genetics Phylogeny Rhodophyta* / genetics
IF 9.412
Resource
Algae NISE-2137