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Open data
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Basic information
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Title | Cryo-EM structure of Holo form of ScBfr in C1 symmetry | |||||||||
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![]() | Bacterioferritin / METAL BINDING PROTEIN / OXIDOREDUCTASE | |||||||||
Function / homology | ![]() ferroxidase / intracellular sequestering of iron ion / ferroxidase activity / ferric iron binding / iron ion transport / iron ion binding / heme binding / cytosol Similarity search - Function | |||||||||
Biological species | ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 4.2 Å | |||||||||
![]() | Jobichen C / Sivaraman J | |||||||||
Funding support | 1 items
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![]() | ![]() Title: Bacterioferritin nanocage structures uncover the biomineralization process in ferritins. Authors: Chacko Jobichen / Tan Ying Chong / Rajesh Rattinam / Sandip Basak / Mahalashmi Srinivasan / Yeu Khai Choong / Kannu Priya Pandey / Tran Bich Ngoc / Jian Shi / Jayaraman Angayarkanni / J Sivaraman / ![]() ![]() ![]() Abstract: Iron is an essential element involved in various metabolic processes. The ferritin family of proteins forms nanocage assembly and is involved in iron oxidation, storage, and mineralization. Although ...Iron is an essential element involved in various metabolic processes. The ferritin family of proteins forms nanocage assembly and is involved in iron oxidation, storage, and mineralization. Although several structures of human ferritins and bacterioferritins have been solved, there is still no complete structure that shows both the trapped Fe-biomineral cluster and the nanocage. Furthermore, whereas the mechanism of iron trafficking has been explained using various approaches, structural details on the biomineralization process (i.e. the formation of the mineral itself) are generally lacking. Here, we report the cryo-electron microscopy (cryo-EM) structures of apoform and biomineral bound form (holoforms) of the bacterioferritin (ScBfr) nanocage and the subunit crystal structure. The holoforms show different stages of Fe-biomineral accumulation inside the nanocage, in which the connections exist in two of the fourfold channels of the nanocage between the C-terminal of the ScBfr monomers and the Fe-biomineral cluster. The mutation and truncation of the bacterioferritin residues involved in these connections significantly reduced the iron and phosphate binding in comparison with those of the wild type and together explain the underlying mechanism. Collectively, our results represent a prototype for the bacterioferritin nanocage, which reveals insight into its biomineralization and the potential channel for bacterioferritin-associated iron trafficking. | |||||||||
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 58.7 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 14 KB 14 KB | Display Display | ![]() |
Images | ![]() | 69.2 KB | ||
Others | ![]() ![]() | 49.6 MB 49.6 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8jb0MC ![]() 7y6fC ![]() 7y6gC ![]() 7y6pC ![]() 8jaxC M: atomic model generated by this map C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
EMDB pages | ![]() ![]() |
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Related items in Molecule of the Month |
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Map
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Voxel size | X=Y=Z: 0.858 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Half map: #2
File | emd_36139_half_map_1.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
-Half map: #1
File | emd_36139_half_map_2.map | ||||||||||||
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Density Histograms |
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Sample components
-Entire : Bacterioferritin
Entire | Name: Bacterioferritin |
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Components |
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-Supramolecule #1: Bacterioferritin
Supramolecule | Name: Bacterioferritin / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1 Details: Bacterioferritin apoform from Streptomyces coelicolor |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 500 KDa |
-Macromolecule #1: Bacterioferritin
Macromolecule | Name: Bacterioferritin / type: protein_or_peptide / ID: 1 / Number of copies: 24 / Enantiomer: LEVO / EC number: ferroxidase |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 19.242629 KDa |
Recombinant expression | Organism: ![]() ![]() |
Sequence | String: MQGDPEVIEF LNEQLTAELT AINQYFLHAK LQDHKGWTKL AKYTRAESFD EMRHAEVLTD RILLLDGLPN YQRLFHVRVG QSVTEMFQA DREVELEAID RLRRGIEVMR AKHDITSANV FEAILADEEH HIDYLETQLD LIEKLGESLY LSTVIEQTQP D PSGPGSL UniProtKB: Bacterioferritin |
-Macromolecule #2: FE (II) ION
Macromolecule | Name: FE (II) ION / type: ligand / ID: 2 / Number of copies: 36 / Formula: FE2 |
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Molecular weight | Theoretical: 55.845 Da |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Buffer | pH: 7.4 |
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Vitrification | Cryogen name: ETHANE |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K3 (6k x 4k) / Average electron dose: 1.8 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 2.5 µm / Nominal defocus min: 0.7000000000000001 µm |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Image processing
Startup model | Type of model: PDB ENTRY PDB model - PDB ID: |
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Final reconstruction | Applied symmetry - Point group: C1 (asymmetric) / Resolution.type: BY AUTHOR / Resolution: 4.2 Å / Resolution method: FSC 0.143 CUT-OFF / Number images used: 11517 |
Initial angle assignment | Type: PROJECTION MATCHING |
Final angle assignment | Type: ANGULAR RECONSTITUTION |