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- EMDB-2758: Cryo-electron microscopy of TibC12-TibA6 octadecamer in resting state -
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Open data
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Basic information
Entry | Database: EMDB / ID: EMD-2758 | |||||||||
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Title | Cryo-electron microscopy of TibC12-TibA6 octadecamer in resting state | |||||||||
![]() | Reconstruction of TibC12-TibA6 complex in resting conformation | |||||||||
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Biological species | ![]() ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 8.9 Å | |||||||||
![]() | Yao Q / Lu QH / Wan XB / Song F / Xu Y / Zamyatina A / Huang N / Zhu P / Shao F | |||||||||
![]() | ![]() Title: A structural mechanism for bacterial autotransporter glycosylation by a dodecameric heptosyltransferase family. Authors: Qing Yao / Qiuhe Lu / Xiaobo Wan / Feng Song / Yue Xu / Mo Hu / Alla Zamyatina / Xiaoyun Liu / Niu Huang / Ping Zhu / Feng Shao / ![]() ![]() Abstract: A large group of bacterial virulence autotransporters including AIDA-I from diffusely adhering E. coli (DAEC) and TibA from enterotoxigenic E. coli (ETEC) require hyperglycosylation for functioning. ...A large group of bacterial virulence autotransporters including AIDA-I from diffusely adhering E. coli (DAEC) and TibA from enterotoxigenic E. coli (ETEC) require hyperglycosylation for functioning. Here we demonstrate that TibC from ETEC harbors a heptosyltransferase activity on TibA and AIDA-I, defining a large family of bacterial autotransporter heptosyltransferases (BAHTs). The crystal structure of TibC reveals a characteristic ring-shape dodecamer. The protomer features an N-terminal β-barrel, a catalytic domain, a β-hairpin thumb, and a unique iron-finger motif. The iron-finger motif contributes to back-to-back dimerization; six dimers form the ring through β-hairpin thumb-mediated hand-in-hand contact. The structure of ADP-D-glycero-β-D-manno-heptose (ADP-D,D-heptose)-bound TibC reveals a sugar transfer mechanism and also the ligand stereoselectivity determinant. Electron-cryomicroscopy analyses uncover a TibC-TibA dodecamer/hexamer assembly with two enzyme molecules binding to one TibA substrate. The complex structure also highlights a high efficient hyperglycosylation of six autotransporter substrates simultaneously by the dodecamer enzyme complex. | |||||||||
History |
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Structure visualization
Movie |
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Structure viewer | EM map: ![]() ![]() ![]() |
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 20.7 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 10.2 KB 10.2 KB | Display Display | ![]() |
Images | ![]() ![]() | 215.6 KB 142.9 KB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
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Links
EMDB pages | ![]() ![]() |
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Map
File | ![]() | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Annotation | Reconstruction of TibC12-TibA6 complex in resting conformation | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.778 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
CCP4 map header:
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-Supplemental data
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Sample components
-Entire : Complex of TibC12-TibA6 octadecamer
Entire | Name: Complex of TibC12-TibA6 octadecamer |
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Components |
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-Supramolecule #1000: Complex of TibC12-TibA6 octadecamer
Supramolecule | Name: Complex of TibC12-TibA6 octadecamer / type: sample / ID: 1000 / Oligomeric state: One TibA monomer binds to one TibC dimer / Number unique components: 2 |
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Molecular weight | Theoretical: 727 KDa |
-Macromolecule #1: TibC
Macromolecule | Name: TibC / type: protein_or_peptide / ID: 1 Details: Ferric ions were attached to specific cysteine residues. Lys230 was substituted by alanine to generate the catalytically inactive mutant. Number of copies: 12 / Oligomeric state: Dodecamer / Recombinant expression: Yes |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 46 KDa |
Recombinant expression | Organism: ![]() ![]() |
-Macromolecule #2: TibA
Macromolecule | Name: TibA / type: protein_or_peptide / ID: 2 / Number of copies: 6 / Recombinant expression: Yes |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 29 KDa |
Recombinant expression | Organism: ![]() ![]() |
-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: 7.6 / Details: 10mM Tris-HCl, 100mM NaCl, 2mM DTT |
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Grid | Details: Quantifoil R2.1, 300 mesh |
Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Instrument: FEI VITROBOT MARK IV Method: 10 ug/ml bacitracin (Sigma) was added to the purified protein to obtain monodispersed particles and make the orientation distribution more anisotropic. Blot for 4 sec using blotting force 2 before plunging. |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Alignment procedure | Legacy - Astigmatism: Objective lens astigmatism was corrected at 155,000 times magnification |
Details | Energy filter turned-off |
Date | May 1, 2013 |
Image recording | Category: CCD / Film or detector model: OTHER / Average electron dose: 18 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal magnification: 81000 |
Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Image processing
Final reconstruction | Applied symmetry - Point group: C6 (6 fold cyclic) / Resolution.type: BY AUTHOR / Resolution: 8.9 Å / Resolution method: OTHER / Software - Name: EMAN2, Relion / Number images used: 18003 |
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-Atomic model buiding 1
Initial model | PDB ID: |
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Software | Name: ![]() |
Refinement | Space: REAL / Protocol: FLEXIBLE FIT |