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-Structure paper
Title | Structure of cyanobacterial photosystem I complexed with ferredoxin at 1.97 Å resolution. |
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Journal, issue, pages | Commun Biol, Vol. 5, Issue 1, Page 951, Year 2022 |
Publish date | Sep 12, 2022 |
Authors | Jiannan Li / Noriyuki Hamaoka / Fumiaki Makino / Akihiro Kawamoto / Yuxi Lin / Matthias Rögner / Marc M Nowaczyk / Young-Ho Lee / Keiichi Namba / Christoph Gerle / Genji Kurisu / |
PubMed Abstract | Photosystem I (PSI) is a light driven electron pump transferring electrons from Cytochrome c (Cyt c) to Ferredoxin (Fd). An understanding of this electron transfer process is hampered by a paucity of ...Photosystem I (PSI) is a light driven electron pump transferring electrons from Cytochrome c (Cyt c) to Ferredoxin (Fd). An understanding of this electron transfer process is hampered by a paucity of structural detail concerning PSI:Fd interface and the possible binding sites of Cyt c. Here we describe the high resolution cryo-EM structure of Thermosynechococcus elongatus BP-1 PSI in complex with Fd and a loosely bound Cyt c. Side chain interactions at the PSI:Fd interface including bridging water molecules are visualized in detail. The structure explains the properties of mutants of PsaE and PsaC that affect kinetics of Fd binding and suggests a molecular switch for the dissociation of Fd upon reduction. Calorimetry-based thermodynamic analyses confirms a single binding site for Fd and demonstrates that PSI:Fd complexation is purely driven by entropy. A possible reaction cycle for the efficient transfer of electrons from Cyt c to Fd via PSI is proposed. |
External links | Commun Biol / PubMed:36097054 / PubMed Central |
Methods | EM (single particle) |
Resolution | 1.97 Å |
Structure data | EMDB-31605, PDB-7fix: |
Chemicals | ChemComp-CL0: ChemComp-CLA: ChemComp-PQN: ChemComp-SF4: ChemComp-BCR: ChemComp-LHG:
ChemComp-UNL: ChemComp-DGD: ChemComp-CA: ChemComp-GAK: ChemComp-HOH: |
Source |
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Keywords | PHOTOSYNTHESIS / Photosystem I / Ferredoxin / Cytochrome c6 |