9UAS

PSI-LHCE-LHCII from Euglena gracilis

Summary for 9UAS

• Entry DOI: 10.2210/pdb9uas/pdb
• EMDB information: 63994
• Descriptor: Photosystem I P700 chlorophyll a apoprotein A2, LhcE6, Lhce8, ... (33 entities in total)
• Functional Keywords: psi, lhce, euglena gracilis, photosynthesis
• Biological source: Euglena gracilis; More
• Total number of polymer chains: 24
• Total formula weight: 936608.51

Authors

Feng, Y. (deposition date: 2025-04-01, release date: 2026-04-01, Last modification date: 2026-06-10)

Primary citation

Feng, Y.,Cao, T.,Su, B.,Zhang, X.,Bai, X.,Guo, K.,Yang, P.
Cryo-EM structure of a photosystem I supercomplex from Euglena gracilis containing pentameric LHCE and dimeric LHCII.
Nat Commun, 17:-, 2026

PubMed Abstract: Euglenophyta is a representative phylum of green-lineage secondary endosymbiotic eukaryotes. These organisms have evolved far-red light-harvesting complexes (LHCs) composed of diadinoxanthin and chlorophyll a/b, which are now classified as the LHCE family. Here we report a 2.35-Å cryo-electron microscopy structure of photosystem I (PSI) supercomplex from Euglena gracilis, with all subunits and their paralogs assigned. This structure reveals a minimal PSI core associated with twelve LHCE and four LHCII subunits. Most LHCE subunits are organized into dimers through a helix C-to-helix C interaction. Two dimers, together with a monomeric LhcE8, assemble into a (2 + 2 + 1)-type LHCE pentamer. The red-shifted pairs in the two LhcE6 subunits likely contribute to far-red absorption. The LHCII subunits form a distinct heterodimer and associate with the PsaF side. Overall, these results provide a structural basis for understanding energy transfer and dissipation, antenna subunit assembly, and far-red light-harvesting strategies in green-lineage secondary endosymbiotic organisms.

PubMed: 41942460
DOI: 10.1038/s41467-026-71601-x

Experimental method

ELECTRON MICROSCOPY (2.35 Å)