8TO5
Central rod disk in C1 symmetry of high-resolution phycobilisome quenched by OCP (local refinement)
Summary for 8TO5
| Entry DOI | 10.2210/pdb8to5/pdb |
| EMDB information | 41434 41435 |
| Descriptor | C-phycocyanin alpha subunit, C-phycocyanin beta subunit, Phycobilisome 32.1 kDa linker polypeptide, phycocyanin-associated, rod 1, ... (6 entities in total) |
| Functional Keywords | complex, light harvesting, pigment, photosynthesis |
| Biological source | Synechocystis sp. PCC 6803 More |
| Total number of polymer chains | 14 |
| Total formula weight | 288545.32 |
| Authors | |
| Primary citation | Sauer, P.V.,Cupellini, L.,Sutter, M.,Bondanza, M.,Dominguez Martin, M.A.,Kirst, H.,Bina, D.,Koh, A.F.,Kotecha, A.,Greber, B.J.,Nogales, E.,Polivka, T.,Mennucci, B.,Kerfeld, C.A. Structural and quantum chemical basis for OCP-mediated quenching of phycobilisomes. Sci Adv, 10:eadk7535-eadk7535, 2024 Cited by PubMed Abstract: Cyanobacteria use large antenna complexes called phycobilisomes (PBSs) for light harvesting. However, intense light triggers non-photochemical quenching, where the orange carotenoid protein (OCP) binds to PBS, dissipating excess energy as heat. The mechanism of efficiently transferring energy from phycocyanobilins in PBS to canthaxanthin in OCP remains insufficiently understood. Using cryo-electron microscopy, we unveiled the OCP-PBS complex structure at 1.6- to 2.1-angstrom resolution, showcasing its inherent flexibility. Using multiscale quantum chemistry, we disclosed the quenching mechanism. Identifying key protein residues, we clarified how canthaxanthin's transition dipole moment in its lowest-energy dark state becomes large enough for efficient energy transfer from phycocyanobilins. Our energy transfer model offers a detailed understanding of the atomic determinants of light harvesting regulation and antenna architecture in cyanobacteria. PubMed: 38578996DOI: 10.1126/sciadv.adk7535 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (1.87 Å) |
Structure validation
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