10kf | pdb_000010kf
Cryo-EM structure of a chemically treated Cyanobacterial Photosystem I core with bound platinum nanoparticles
Structural highlights
FunctionPSAA_SYNP6 PsaA and PsaB bind P700, the primary electron donor of photosystem I (PSI), as well as the electron acceptors A0, A1 and FX. PSI is a plastocyanin/cytochrome c6-ferredoxin oxidoreductase, converting photonic excitation into a charge separation, which transfers an electron from the donor P700 chlorophyll pair to the spectroscopically characterized acceptors A0, A1, FX, FA and FB in turn. Oxidized P700 is reduced on the lumenal side of the thylakoid membrane by plastocyanin or cytochrome c6. Publication Abstract from PubMedDirect solar-to-chemical conversion offers a compelling route to clean, dispatchable energy. Photosystem I (PSI), an evolutionarily optimized light-driven oxidoreductase central to oxygenic photosynthesis, can be repurposed for direct solar-fuel production by efficiently coupling its photochemistry to catalysts, thereby storing sunlight as chemical energy in the H-H bond of H2. One promising architecture integrates PSI with Pt nanoparticle (PtNP) catalysts to create photocatalytic PSI-PtNP biohybrids. Advancing these systems requires molecular-level insight into protein-nanoparticle interactions and the bio-nano electron transfer pathways that govern activity; however, progress has been constrained by limited structural data to guide rational design. Here, we present two molecular structures of active PSI-PtNP assemblies that (a) compare thermophilic and mesophilic PSI scaffolds and (b) probe how removal of the terminal [4Fe-4S] clusters and stromal subunits in PSI reshapes protein-nanoparticle interfaces and photocatalysis. Structural analyses and molecular dynamics simulations define the interface topology, electrostatics, and cofactor-to-nanoparticle distances, revealing key molecular features that control biohybrid formation and electron transfer efficiency. These data establish mechanistic links between scaffold composition, bio-nano interface geometry, and catalytic performance, yielding design principles for optimizing PSI-PtNP architectures. The resulting structure-function insights provide a blueprint for engineering PSI-based solar-fuels systems and, more broadly, inform the design of protein-nanomaterial interfaces for light-driven catalysis. Molecular design principles for Photosystem I-based biohybrid solar fuel catalysts.,Emerson MD, Damaraju SNS, Short AH, Alvord ZB, Palmer ZA, Mehra HS, Brininger CM, Vermaas JV, Utschig LM, Gisriel CJ bioRxiv [Preprint]. 2026 Mar 25:2026.03.23.713776. doi: , 10.64898/2026.03.23.713776. PMID:41929101[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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