+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-12697 | |||||||||
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Title | Structure of a Minimal Photosystem I | |||||||||
Map data | ||||||||||
Sample |
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Keywords | Photosystem I / excitation energy transfer / cyanobacteria / minimal structure / PHOTOSYNTHESIS | |||||||||
Function / homology | Function and homology information photosystem I reaction center / photosystem I / photosynthetic electron transport in photosystem I / photosystem I / chlorophyll binding / plasma membrane-derived thylakoid membrane / photosynthesis / 4 iron, 4 sulfur cluster binding / electron transfer activity / oxidoreductase activity ...photosystem I reaction center / photosystem I / photosynthetic electron transport in photosystem I / photosystem I / chlorophyll binding / plasma membrane-derived thylakoid membrane / photosynthesis / 4 iron, 4 sulfur cluster binding / electron transfer activity / oxidoreductase activity / magnesium ion binding / metal ion binding / plasma membrane Similarity search - Function | |||||||||
Biological species | Synechocystis sp. (strain PCC 6803 / Kazusa) (bacteria) | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 4.31 Å | |||||||||
Authors | Nelson N / Caspy I | |||||||||
Funding support | Israel, 1 items
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Citation | Journal: J Am Chem Soc / Year: 2021 Title: Two-Dimensional Electronic Spectroscopy of a Minimal Photosystem I Complex Reveals the Rate of Primary Charge Separation. Authors: Parveen Akhtar / Ido Caspy / Paweł J Nowakowski / Tirupathi Malavath / Nathan Nelson / Howe-Siang Tan / Petar H Lambrev / Abstract: Photosystem I (PSI), found in all oxygenic photosynthetic organisms, uses solar energy to drive electron transport with nearly 100% quantum efficiency, thanks to fast energy transfer among antenna ...Photosystem I (PSI), found in all oxygenic photosynthetic organisms, uses solar energy to drive electron transport with nearly 100% quantum efficiency, thanks to fast energy transfer among antenna chlorophylls and charge separation in the reaction center. There is no complete consensus regarding the kinetics of the elementary steps involved in the overall trapping, especially the rate of primary charge separation. In this work, we employed two-dimensional coherent electronic spectroscopy to follow the dynamics of energy and electron transfer in a monomeric PSI complex from PCC 6803, containing only subunits A-E, K, and M, at 77 K. We also determined the structure of the complex to 4.3 Å resolution by cryoelectron microscopy with refinements to 2.5 Å. We applied structure-based modeling using a combined Redfield-Förster theory to compute the excitation dynamics. The absorptive 2D electronic spectra revealed fast excitonic/vibronic relaxation on time scales of 50-100 fs from the high-energy side of the absorption spectrum. Antenna excitations were funneled within 1 ps to a small pool of chlorophylls absorbing around 687 nm, thereafter decaying with 4-20 ps lifetimes, independently of excitation wavelength. Redfield-Förster energy transfer computations showed that the kinetics is limited by transfer from these red-shifted pigments. The rate of primary charge separation, upon direct excitation of the reaction center, was determined to be 1.2-1.5 ps. This result implies activationless electron transfer in PSI. | |||||||||
History |
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-Structure visualization
Movie |
Movie viewer |
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Structure viewer | EM map: SurfViewMolmilJmol/JSmol |
Supplemental images |
-Downloads & links
-EMDB archive
Map data | emd_12697.map.gz | 78.3 MB | EMDB map data format | |
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Header (meta data) | emd-12697-v30.xml emd-12697.xml | 19.6 KB 19.6 KB | Display Display | EMDB header |
FSC (resolution estimation) | emd_12697_fsc.xml | 10.1 KB | Display | FSC data file |
Images | emd_12697.png | 66.7 KB | ||
Filedesc metadata | emd-12697.cif.gz | 7 KB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-12697 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-12697 | HTTPS FTP |
-Validation report
Summary document | emd_12697_validation.pdf.gz | 640.4 KB | Display | EMDB validaton report |
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Full document | emd_12697_full_validation.pdf.gz | 640 KB | Display | |
Data in XML | emd_12697_validation.xml.gz | 10.9 KB | Display | |
Data in CIF | emd_12697_validation.cif.gz | 14.5 KB | Display | |
Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-12697 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-12697 | HTTPS FTP |
-Related structure data
Related structure data | 7o1vMC M: atomic model generated by this map C: citing same article (ref.) |
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Similar structure data |
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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Related items in Molecule of the Month |
-Map
File | Download / File: emd_12697.map.gz / Format: CCP4 / Size: 83.7 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 0.8328 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
CCP4 map header:
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-Supplemental data
-Sample components
+Entire : Minimal Photosystem I
+Supramolecule #1: Minimal Photosystem I
+Macromolecule #1: Photosystem I P700 chlorophyll a apoprotein A1
+Macromolecule #2: Photosystem I P700 chlorophyll a apoprotein A2
+Macromolecule #3: Photosystem I iron-sulfur center
+Macromolecule #4: Photosystem I reaction center subunit II
+Macromolecule #5: Photosystem I reaction center subunit IV
+Macromolecule #6: Photosystem I reaction center subunit PsaK 2
+Macromolecule #7: Photosystem I reaction center subunit XII
+Macromolecule #8: CHLOROPHYLL A
+Macromolecule #9: PHYLLOQUINONE
+Macromolecule #10: BETA-CAROTENE
+Macromolecule #11: 1,2-DIPALMITOYL-PHOSPHATIDYL-GLYCEROLE
+Macromolecule #12: 1,2-DISTEAROYL-MONOGALACTOSYL-DIGLYCERIDE
+Macromolecule #13: IRON/SULFUR CLUSTER
+Macromolecule #14: beta,beta-caroten-4-one
+Macromolecule #15: 1,2-DI-O-ACYL-3-O-[6-DEOXY-6-SULFO-ALPHA-D-GLUCOPYRANOSYL]-SN-GLYCEROL
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | single particle reconstruction |
Aggregation state | particle |
-Sample preparation
Buffer | pH: 6.5 |
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Vitrification | Cryogen name: ETHANE |
-Electron microscopy
Microscope | FEI TITAN KRIOS |
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Specialist optics | Phase plate: VOLTA PHASE PLATE |
Image recording | Film or detector model: GATAN K3 (6k x 4k) / Number real images: 2493 / Average electron dose: 43.6 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD |
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |