7Y8A
Cryo-EM structure of cryptophyte photosystem I
Summary for 7Y8A
| Entry DOI | 10.2210/pdb7y8a/pdb |
| EMDB information | 33683 |
| Descriptor | ACPI-1, Photosystem I P700 chlorophyll a apoprotein A1, Photosystem I P700 chlorophyll a apoprotein A2, ... (39 entities in total) |
| Functional Keywords | cryptophyte, photosystem i, evolution, photosynthesis |
| Biological source | Chroomonas placoidea More |
| Total number of polymer chains | 26 |
| Total formula weight | 863763.55 |
| Authors | Zhao, L.S.,Zhang, Y.Z.,Liu, L.N.,Li, K. (deposition date: 2022-06-23, release date: 2023-04-12, Last modification date: 2024-11-13) |
| Primary citation | Zhao, L.S.,Wang, P.,Li, K.,Zhang, Q.B.,He, F.Y.,Li, C.Y.,Su, H.N.,Chen, X.L.,Liu, L.N.,Zhang, Y.Z. Structural basis and evolution of the photosystem I-light-harvesting supercomplex of cryptophyte algae. Plant Cell, 35:2449-2463, 2023 Cited by PubMed Abstract: Cryptophyte plastids originated from a red algal ancestor through secondary endosymbiosis. Cryptophyte photosystem I (PSI) associates with transmembrane alloxanthin-chlorophyll a/c proteins (ACPIs) as light-harvesting complexes (LHCs). Here, we report the structure of the photosynthetic PSI-ACPI supercomplex from the cryptophyte Chroomonas placoidea at 2.7-Å resolution obtained by crygenic electron microscopy. Cryptophyte PSI-ACPI represents a unique PSI-LHCI intermediate in the evolution from red algal to diatom PSI-LHCI. The PSI-ACPI supercomplex is composed of a monomeric PSI core containing 14 subunits, 12 of which originated in red algae, 1 diatom PsaR homolog, and an additional peptide. The PSI core is surrounded by 14 ACPI subunits that form 2 antenna layers: an inner layer with 11 ACPIs surrounding the PSI core and an outer layer containing 3 ACPIs. A pigment-binding subunit that is not present in any other previously characterized PSI-LHCI complexes, ACPI-S, mediates the association and energy transfer between the outer and inner ACPIs. The extensive pigment network of PSI-ACPI ensures efficient light harvesting, energy transfer, and dissipation. Overall, the PSI-LHCI structure identified in this study provides a framework for delineating the mechanisms of energy transfer in cryptophyte PSI-LHCI and for understanding the evolution of photosynthesis in the red lineage, which occurred via secondary endosymbiosis. PubMed: 36943796DOI: 10.1093/plcell/koad087 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.71 Å) |
Structure validation
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