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Open data
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Basic information
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Title | Azotobacter vinelandii MoFeP (C2 symmetry) | ||||||||||||
![]() | Sharpened EM map of MoFeP; C2 symmetry | ||||||||||||
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![]() | Nitrogenase / FeMoCo / nitrogen / P-cluster / METAL BINDING PROTEIN | ||||||||||||
Function / homology | ![]() molybdenum-iron nitrogenase complex / nitrogenase / nitrogenase activity / nitrogen fixation / iron-sulfur cluster binding / ATP binding / metal ion binding Similarity search - Function | ||||||||||||
Biological species | ![]() | ||||||||||||
Method | single particle reconstruction / cryo EM / Resolution: 2.67 Å | ||||||||||||
![]() | Narehood SM / Cook BD / Srisantitham S / Eng VH / Shiau A / Britt RD / Herzik MA / Tezcan FA | ||||||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural basis for the conformational protection of nitrogenase from O. Authors: Sarah M Narehood / Brian D Cook / Suppachai Srisantitham / Vanessa H Eng / Angela A Shiau / Kelly L McGuire / R David Britt / Mark A Herzik / F Akif Tezcan / ![]() Abstract: The low reduction potentials required for the reduction of dinitrogen (N) render metal-based nitrogen-fixation catalysts vulnerable to irreversible damage by dioxygen (O). Such O sensitivity ...The low reduction potentials required for the reduction of dinitrogen (N) render metal-based nitrogen-fixation catalysts vulnerable to irreversible damage by dioxygen (O). Such O sensitivity represents a major conundrum for the enzyme nitrogenase, as a large fraction of nitrogen-fixing organisms are either obligate aerobes or closely associated with O-respiring organisms to support the high energy demand of catalytic N reduction. To counter O damage to nitrogenase, diazotrophs use O scavengers, exploit compartmentalization or maintain high respiration rates to minimize intracellular O concentrations. A last line of damage control is provided by the 'conformational protection' mechanism, in which a [2Fe:2S] ferredoxin-family protein termed FeSII (ref. ) is activated under O stress to form an O-resistant complex with the nitrogenase component proteins. Despite previous insights, the molecular basis for the conformational O protection of nitrogenase and the mechanism of FeSII activation are not understood. Here we report the structural characterization of the Azotobacter vinelandii FeSII-nitrogenase complex by cryo-electron microscopy. Our studies reveal a core complex consisting of two molybdenum-iron proteins (MoFePs), two iron proteins (FePs) and one FeSII homodimer, which polymerize into extended filaments. In this three-protein complex, FeSII mediates an extensive network of interactions with MoFeP and FeP to position their iron-sulphur clusters in catalytically inactive but O-protected states. The architecture of the FeSII-nitrogenase complex is confirmed by solution studies, which further indicate that the activation of FeSII involves an oxidation-induced conformational change. | ||||||||||||
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 203.9 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 25.1 KB 25.1 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() | 12.7 KB | Display | ![]() |
Images | ![]() | 50.6 KB | ||
Masks | ![]() | 216 MB | ![]() | |
Filedesc metadata | ![]() | 7.4 KB | ||
Others | ![]() ![]() ![]() | 108.1 MB 199.9 MB 199.9 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 9ctzMC ![]() 9cu0C ![]() 9cu1C ![]() 9cu2C 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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Annotation | Sharpened EM map of MoFeP; C2 symmetry | ||||||||||||||||||||||||||||||||||||
Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 0.735 Å | ||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Mask #1
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Density Histograms |
-Additional map: Unsharpened EM map of MoFeP; C2 symmetry
File | emd_45923_additional_1.map | ||||||||||||
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Annotation | Unsharpened EM map of MoFeP; C2 symmetry | ||||||||||||
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Density Histograms |
-Half map: Half map B of MoFeP; C2 symmetry
File | emd_45923_half_map_1.map | ||||||||||||
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Annotation | Half map B of MoFeP; C2 symmetry | ||||||||||||
Projections & Slices |
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Density Histograms |
-Half map: Half map A of MoFeP; C2 symmetry
File | emd_45923_half_map_2.map | ||||||||||||
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Annotation | Half map A of MoFeP; C2 symmetry | ||||||||||||
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Density Histograms |
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Sample components
-Entire : Azotobacter vinelandii MoFeP (C2 symmetry)
Entire | Name: Azotobacter vinelandii MoFeP (C2 symmetry) |
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Components |
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-Supramolecule #1: Azotobacter vinelandii MoFeP (C2 symmetry)
Supramolecule | Name: Azotobacter vinelandii MoFeP (C2 symmetry) / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1-#2 |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 230 KDa |
-Macromolecule #1: Nitrogenase molybdenum-iron protein alpha chain
Macromolecule | Name: Nitrogenase molybdenum-iron protein alpha chain / type: protein_or_peptide / ID: 1 / Number of copies: 2 / Enantiomer: LEVO / EC number: nitrogenase |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 55.363043 KDa |
Sequence | String: MTGMSREEVE SLIQEVLEVY PEKARKDRNK HLAVNDPAVT QSKKCIISNK KSQPGLMTIR GCAYAGSKGV VWGPIKDMIH ISHGPVGCG QYSRAGRRNY YIGTTGVNAF VTMNFTSDFQ EKDIVFGGDK KLAKLIDEVE TLFPLNKGIS VQSECPIGLI G DDIESVSK ...String: MTGMSREEVE SLIQEVLEVY PEKARKDRNK HLAVNDPAVT QSKKCIISNK KSQPGLMTIR GCAYAGSKGV VWGPIKDMIH ISHGPVGCG QYSRAGRRNY YIGTTGVNAF VTMNFTSDFQ EKDIVFGGDK KLAKLIDEVE TLFPLNKGIS VQSECPIGLI G DDIESVSK VKGAELSKTI VPVRCEGFRG VSQSLGHHIA NDAVRDWVLG KRDEDTTFAS TPYDVAIIGD YNIGGDAWSS RI LLEEMGL RCVAQWSGDG SISEIELTPK VKLNLVHCYR SMNYISRHME EKYGIPWMEY NFFGPTKTIE SLRAIAAKFD ESI QKKCEE VIAKYKPEWE AVVAKYRPRL EGKRVMLYIG GLRPRHVIGA YEDLGMEVVG TGYEFAHNDD YDRTMKEMGD STLL YDDVT GYEFEEFVKR IKPDLIGSGI KEKFIFQKMG IPFREMHSWD YSGPYHGFDG FAIFARDMDM TLNNPCWKKL QAPWE ASEG AEKVAASA UniProtKB: Nitrogenase molybdenum-iron protein alpha chain |
-Macromolecule #2: Nitrogenase molybdenum-iron protein beta chain
Macromolecule | Name: Nitrogenase molybdenum-iron protein beta chain / type: protein_or_peptide / ID: 2 / Number of copies: 2 / Enantiomer: LEVO / EC number: nitrogenase |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 59.535879 KDa |
Sequence | String: MSQQVDKIKA SYPLFLDQDY KDMLAKKRDG FEEKYPQDKI DEVFQWTTTK EYQELNFQRE ALTVNPAKAC QPLGAVLCAL GFEKTMPYV HGSQGCVAYF RSYFNRHFRE PVSCVSDSMT EDAAVFGGQQ NMKDGLQNCK ATYKPDMIAV STTCMAEVIG D DLNAFINN ...String: MSQQVDKIKA SYPLFLDQDY KDMLAKKRDG FEEKYPQDKI DEVFQWTTTK EYQELNFQRE ALTVNPAKAC QPLGAVLCAL GFEKTMPYV HGSQGCVAYF RSYFNRHFRE PVSCVSDSMT EDAAVFGGQQ NMKDGLQNCK ATYKPDMIAV STTCMAEVIG D DLNAFINN SKKEGFIPDE FPVPFAHTPS FVGSHVTGWD NMFEGIARYF TLKSMDDKVV GSNKKINIVP GFETYLGNFR VI KRMLSEM GVGYSLLSDP EEVLDTPADG QFRMYAGGTT QEEMKDAPNA LNTVLLQPWH LEKTKKFVEG TWKHEVPKLN IPM GLDWTD EFLMKVSEIS GQPIPASLTK ERGRLVDMMT DSHTWLHGKR FALWGDPDFV MGLVKFLLEL GCEPVHILCH NGNK RWKKA VDAILAASPY GKNATVYIGK DLWHLRSLVF TDKPDFMIGN SYGKFIQRDT LHKGKEFEVP LIRIGFPIFD RHHLH RSTT LGYEGAMQIL TTLVNSILER LDEETRGMQA TDYNHDLVR UniProtKB: Nitrogenase molybdenum-iron protein beta chain |
-Macromolecule #3: 3-HYDROXY-3-CARBOXY-ADIPIC ACID
Macromolecule | Name: 3-HYDROXY-3-CARBOXY-ADIPIC ACID / type: ligand / ID: 3 / Number of copies: 2 / Formula: HCA |
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Molecular weight | Theoretical: 206.15 Da |
Chemical component information | ![]() ChemComp-HCA: |
-Macromolecule #4: iron-sulfur-molybdenum cluster with interstitial carbon
Macromolecule | Name: iron-sulfur-molybdenum cluster with interstitial carbon type: ligand / ID: 4 / Number of copies: 2 / Formula: ICS |
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Molecular weight | Theoretical: 787.451 Da |
Chemical component information | ![]() ChemComp-ICE: |
-Macromolecule #5: FE (III) ION
Macromolecule | Name: FE (III) ION / type: ligand / ID: 5 / Number of copies: 2 / Formula: FE |
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Molecular weight | Theoretical: 55.845 Da |
-Macromolecule #6: FE(8)-S(7) CLUSTER
Macromolecule | Name: FE(8)-S(7) CLUSTER / type: ligand / ID: 6 / Number of copies: 2 / Formula: CLF |
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Molecular weight | Theoretical: 671.215 Da |
Chemical component information | ![]() ChemComp-CLF: |
-Macromolecule #7: water
Macromolecule | Name: water / type: ligand / ID: 7 / Number of copies: 924 / Formula: HOH |
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Molecular weight | Theoretical: 18.015 Da |
Chemical component information | ![]() ChemComp-HOH: |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Concentration | 2.5 mg/mL | ||||||||||||||||||
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Buffer | pH: 8 Component:
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Grid | Model: Quantifoil / Material: COPPER / Mesh: 300 / Support film - Material: CARBON / Support film - topology: HOLEY / Pretreatment - Type: GLOW DISCHARGE / Pretreatment - Time: 45 sec. | ||||||||||||||||||
Vitrification | Cryogen name: ETHANE / Chamber humidity: 75 % / Chamber temperature: 298.15 K / Instrument: SPOTITON Details: Samples were frozen with the SPT Labtech chameleon. |
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Electron microscopy
Microscope | TFS KRIOS |
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Specialist optics | Energy filter - Name: TFS Selectris X / Energy filter - Slit width: 10 eV |
Image recording | Film or detector model: FEI FALCON IV (4k x 4k) / Digitization - Dimensions - Width: 4096 pixel / Digitization - Dimensions - Height: 4096 pixel / Number grids imaged: 3 / Number real images: 8049 / Average exposure time: 5.0 sec. / Average electron dose: 60.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Cs: 2.7 mm / Nominal defocus max: 2.5 µm / Nominal defocus min: 0.75 µm / Nominal magnification: 165000 |
Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |