Structural and quantum chemical basis for OCP-mediated quenching of phycobilisomes.
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Embargo End Date
ICR Authors
Authors
Sauer, PV
Cupellini, L
Sutter, M
Bondanza, M
Domínguez Martin, MA
Kirst, H
Bína, D
Koh, AF
Kotecha, A
Greber, BJ
Nogales, E
Polívka, T
Mennucci, B
Kerfeld, CA
Cupellini, L
Sutter, M
Bondanza, M
Domínguez Martin, MA
Kirst, H
Bína, D
Koh, AF
Kotecha, A
Greber, BJ
Nogales, E
Polívka, T
Mennucci, B
Kerfeld, CA
Document Type
Journal Article
Date
2024-04-05
Date Accepted
2024-03-04
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.
Citation
Science Advances, 2024, 10 (14), pp. eadk7535 -
Source Title
Science Advances
Publisher
AMER ASSOC ADVANCEMENT SCIENCE
ISSN
2375-2548
eISSN
2375-2548
2375-2548
2375-2548
Collections
Research Team
Struct Biol DNA repair