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Open data
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Basic information
| Entry | Database: PDB / ID: 31cj | |||||||||||||||||||||||||||
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| Title | Reduced E.coli aerotaxis receptor | |||||||||||||||||||||||||||
Components | Aerotaxis receptor | |||||||||||||||||||||||||||
Keywords | FLAVOPROTEIN / Chemotaxis / Energy Taxis / Redox Sensing / Transmembrane Signaling / Cryo-EM / DdEER Spectroscopy | |||||||||||||||||||||||||||
| Function / homology | Function and homology informationpositive aerotaxis / chemotaxis / transmembrane signaling receptor activity / signal transduction / identical protein binding / plasma membrane Similarity search - Function | |||||||||||||||||||||||||||
| Biological species | ![]() | |||||||||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.3 Å | |||||||||||||||||||||||||||
Authors | Olsthoorn, F.A. / Muok, A.R. / Xu, Y. / Crane, B.R. | |||||||||||||||||||||||||||
| Funding support | United States, 1items
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Citation | Journal: bioRxiv / Year: 2026Title: Signaling mechanism of the transmembrane energy receptor Aer. Authors: Flory A Olsthoorn / Alise R Muok / Zachary A Maschmann / Yajie Xu / Siddarth Chandrasekaran / Robert Dunleavy / Brian R Crane Abstract: The aerotaxis receptor Aer is a bacterial chemoreceptor that senses intracellular redox changes via an N-terminal PAS domain bound to a flavin adenine dinucleotide (FAD) cofactor. Distinct from ...The aerotaxis receptor Aer is a bacterial chemoreceptor that senses intracellular redox changes via an N-terminal PAS domain bound to a flavin adenine dinucleotide (FAD) cofactor. Distinct from canonical methyl-accepting chemotaxis proteins (MCPs) such as Tar/Tsr, Aer lacks a periplasmic ligand-binding domain and adaptive methylation, transmitting conformational signals laterally from the PAS domain to the HAMP domain and the methylation helix cap (MH-cap) of the kinase control domain (KCD). To elucidate the Aer signalling mechanism, we determined cryo-electron microscopy (cryo-EM) structures of full-length Aer in oxidized flavin quinone (kinase-on) and anionic semiquinone (kinase-off) states. Structural comparison revealed redox-linked rearrangements of the FAD-binding pocket, reorientation of PAS-HAMP interactions, and strikingly altered MH-cap stability. PAS-MH-cap contact in the oxidized state compressed the receptor and stabilized proximal KCD helices, whereas reduction disrupted these contacts, increasing KCD flexibility. To probe distal effects on KCD architecture, we performed nanodisc reconstitution and pulse dipolar ESR spectroscopy on spin-labelled positions along the four-helix bundle. Distance distributions indicated redox-dependent changes in helix separation, particularly at the C-terminal MH2 region, consistent with PAS-driven loosening of KCD packing in kinase-off states. These data support a model in which FAD redox chemistry reorganizes flavin pocket residues that in turn subtly alter PAS conformation to influence PAS-HAMP and PAS-MH-cap packing and hence KCD conformational stability. The findings reveal an Aer-specific signaling axis distinct from periplasmic-ligand binding MCPs that has adapted MCP architecture for lateral PAS input and and cytoplasmic redox sensing. | |||||||||||||||||||||||||||
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Structure visualization
| Structure viewer | Molecule: Molmil Jmol/JSmol |
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Downloads & links
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Download
| PDBx/mmCIF format | 31cj.cif.gz | 185 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb31cj.ent.gz | 143.4 KB | Display | PDB format |
| PDBx/mmJSON format | 31cj.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/1c/31cj ftp://data.pdbj.org/pub/pdb/validation_reports/1c/31cj | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 58290MC ![]() 31ckC M: map data used to model this data C: citing same article ( |
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| Similar structure data | Similarity search - Function & homology F&H Search |
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Links
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Assembly
| Deposited unit | ![]()
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Components
| #1: Protein | Mass: 58002.648 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() #2: Chemical | Has ligand of interest | Y | Has protein modification | N | |
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-Experimental details
-Experiment
| Experiment | Method: ELECTRON MICROSCOPY |
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| EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
| Component | Name: LMNG-solubilized Aer bound to cofactor FAD in an ASQ state Type: COMPLEX / Entity ID: #1 / Source: RECOMBINANT | ||||||||||||||||||||||||||||||
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| Molecular weight | Value: 0.11 MDa / Experimental value: NO | ||||||||||||||||||||||||||||||
| Source (natural) | Organism: ![]() | ||||||||||||||||||||||||||||||
| Source (recombinant) | Organism: ![]() | ||||||||||||||||||||||||||||||
| Buffer solution | pH: 7.5 Details: 25 mM Tris, 150 mM NaCl, 5% glycerol, 0.002% LMNG, 1 mM sodium dithionite | ||||||||||||||||||||||||||||||
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| Specimen | Conc.: 0.5 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES Details: Sample was degassed in a mixed hydrogen (3%) and nitrogen (97%) atmosphere inside a Coy chamber and incubated with 1 mM dithionite prior to vitrification. | ||||||||||||||||||||||||||||||
| Specimen support | Grid material: COPPER / Grid mesh size: 200 divisions/in. / Grid type: Quantifoil R1.2/1.3 | ||||||||||||||||||||||||||||||
| Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 90 % / Chamber temperature: 279 K Details: Vitrification carried out in a mixed hydrogen (3%) and nitrogen (97%) atmosphere inside a Coy chamber. |
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Electron microscopy imaging
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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| Microscopy | Model: TFS KRIOS |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal magnification: 130000 X / Nominal defocus max: 2400 nm / Nominal defocus min: 800 nm |
| Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
| Image recording | Electron dose: 54 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) / Num. of grids imaged: 1 / Num. of real images: 11975 |
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Processing
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| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Symmetry | Point symmetry: C2 (2 fold cyclic) | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| 3D reconstruction | Resolution: 3.3 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 77320 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Atomic model building | B value: 125.6 / Protocol: FLEXIBLE FIT / Space: REAL | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Atomic model building | Source name: AlphaFold / Type: in silico model |
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About Yorodumi






United States, 1items
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FIELD EMISSION GUN