+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-9877 | |||||||||
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Title | Structure of PSI dimer from Anabaena | |||||||||
Map data | ||||||||||
Sample |
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Biological species | Nostoc sp. PCC 7120 (bacteria) | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 4.0 Å | |||||||||
Authors | Kato K / Nagao R / Shen JR / Miyazaki N / Akita F | |||||||||
Citation | Journal: Nat Commun / Year: 2019 Title: Structure of a cyanobacterial photosystem I tetramer revealed by cryo-electron microscopy. Authors: Koji Kato / Ryo Nagao / Tian-Yi Jiang / Yoshifumi Ueno / Makio Yokono / Siu Kit Chan / Mai Watanabe / Masahiko Ikeuchi / Jian-Ren Shen / Seiji Akimoto / Naoyuki Miyazaki / Fusamichi Akita / Abstract: Photosystem I (PSI) functions to harvest light energy for conversion into chemical energy. The organisation of PSI is variable depending on the species of organism. Here we report the structure of a ...Photosystem I (PSI) functions to harvest light energy for conversion into chemical energy. The organisation of PSI is variable depending on the species of organism. Here we report the structure of a tetrameric PSI core isolated from a cyanobacterium, Anabaena sp. PCC 7120, analysed by single-particle cryo-electron microscopy (cryo-EM) at 3.3 Å resolution. The PSI tetramer has a C2 symmetry and is organised in a dimer of dimers form. The structure reveals interactions at the dimer-dimer interface and the existence of characteristic pigment orientations and inter-pigment distances within the dimer units that are important for unique excitation energy transfer. In particular, characteristic residues of PsaL are identified to be responsible for the formation of the tetramer. Time-resolved fluorescence analyses showed that the PSI tetramer has an enhanced excitation-energy quenching. These structural and spectroscopic findings provide insights into the physiological significance of the PSI tetramer and evolutionary changes of the PSI organisations. | |||||||||
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_9877.map.gz | 19.4 MB | EMDB map data format | |
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Header (meta data) | emd-9877-v30.xml emd-9877.xml | 12.2 KB 12.2 KB | Display Display | EMDB header |
FSC (resolution estimation) | emd_9877_fsc.xml | 15.6 KB | Display | FSC data file |
Images | emd_9877.png | 61.6 KB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-9877 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-9877 | HTTPS FTP |
-Validation report
Summary document | emd_9877_validation.pdf.gz | 77.6 KB | Display | EMDB validaton report |
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Full document | emd_9877_full_validation.pdf.gz | 76.7 KB | Display | |
Data in XML | emd_9877_validation.xml.gz | 493 B | Display | |
Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-9877 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-9877 | HTTPS FTP |
-Related structure data
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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-Map
File | Download / File: emd_9877.map.gz / Format: CCP4 / Size: 325 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: 1.12 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 : PSI dimer
Entire | Name: PSI dimer |
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Components |
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-Supramolecule #1: PSI dimer
Supramolecule | Name: PSI dimer / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1-#12 |
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Source (natural) | Organism: Nostoc sp. PCC 7120 (bacteria) |
Molecular weight | Theoretical: 700 KDa |
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | single particle reconstruction |
Aggregation state | particle |
-Sample preparation
Concentration | 0.014 mg/mL | ||||||
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Buffer | pH: 6.5 / Component:
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Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 277 K / Instrument: FEI VITROBOT MARK IV |
-Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: FEI FALCON III (4k x 4k) / Average electron dose: 40.0 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 |
+Image processing
-Atomic model buiding 1
Initial model | PDB ID: |
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Refinement | Space: REAL / Protocol: FLEXIBLE FIT / Target criteria: Correlation coefficient |