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Open data
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Basic information
| Entry | Database: PDB / ID: 9nae | ||||||||||||
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| Title | MicroED structure of papain co-crystallized with E-64 | ||||||||||||
Components | Papain | ||||||||||||
Keywords | HYDROLASE / Inhibitor / Complex / MicroED / Protease | ||||||||||||
| Function / homology | Function and homology informationpapain / serpin family protein binding / cysteine-type peptidase activity / proteolysis Similarity search - Function | ||||||||||||
| Biological species | ![]() | ||||||||||||
| Method | ELECTRON CRYSTALLOGRAPHY / electron crystallography / MOLECULAR REPLACEMENT / cryo EM / Resolution: 2.3 Å | ||||||||||||
Authors | Vlahakis, N. / Rodriguez, J.A. | ||||||||||||
| Funding support | United States, 3items
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Citation | Journal: bioRxiv / Year: 2025Title: Combining MicroED and native mass spectrometry for structural discovery of enzyme-biosynthetic inhibitor complexes. Authors: Niko W Vlahakis / Cameron W Flowers / Mengting Liu / Matthew Agdanowski / Samuel Johnson / Jacob A Summers / Catherine Keyser / Phoebe Russell / Samuel Rose / Julien Orlans / Nima Adhami / ...Authors: Niko W Vlahakis / Cameron W Flowers / Mengting Liu / Matthew Agdanowski / Samuel Johnson / Jacob A Summers / Catherine Keyser / Phoebe Russell / Samuel Rose / Julien Orlans / Nima Adhami / Yu Chen / Michael R Sawaya / Shibom Basu / Daniele de Sanctis / Soichi Wakatsuki / Hosea M Nelson / Joseph A Loo / Yi Tang / Jose A Rodriguez / ![]() Abstract: With the goal of accelerating the discovery of small molecule-protein complexes, we leverage fast, low-dose, event based electron counting microcrystal electron diffraction (MicroED) data collection ...With the goal of accelerating the discovery of small molecule-protein complexes, we leverage fast, low-dose, event based electron counting microcrystal electron diffraction (MicroED) data collection and native mass spectrometry. This approach resolves structures of the epoxide-based cysteine protease inhibitor, and natural product, E-64, and its biosynthetic analogs bound to the model cysteine protease, papain. The combined structural power of MicroED and the analytical capabilities of native mass spectrometry (ED-MS) allows assignment of papain structures bound to E-64-like ligands with data obtained from crystal slurries soaked with mixtures of known inhibitors, and crude biosynthetic reactions. ED-MS further discriminates the highest-affinity ligand soaked into microcrystals from a broad inhibitor cocktail, and identifies multiple similarly high-affinity ligands soaked into microcrystals simultaneously. This extends to libraries of printed ligands dispensed directly onto TEM grids and later soaked with papain microcrystal slurries. ED-MS identifies papain binding to its preferred natural products, by showing that two analogues of E-64 outcompete others in binding to papain crystals, and by detecting papain bound to E-64 and an analogue from crude biosynthetic reactions, without purification. This illustrates the utility of ED-MS for natural product ligand discovery and for structure-based screening of small molecule binders to macromolecular targets. | ||||||||||||
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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 | 9nae.cif.gz | 57.1 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb9nae.ent.gz | 38 KB | Display | PDB format |
| PDBx/mmJSON format | 9nae.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Summary document | 9nae_validation.pdf.gz | 486.7 KB | Display | wwPDB validaton report |
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| Full document | 9nae_full_validation.pdf.gz | 487.4 KB | Display | |
| Data in XML | 9nae_validation.xml.gz | 11.6 KB | Display | |
| Data in CIF | 9nae_validation.cif.gz | 14.1 KB | Display | |
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/na/9nae ftp://data.pdbj.org/pub/pdb/validation_reports/na/9nae | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 9n9dC ![]() 9nagC ![]() 9naoC ![]() 9narC ![]() 9natC ![]() 9naxC ![]() 9nayC ![]() 9nb2C ![]() 9nb4C ![]() 9nb7C ![]() 9nbfC ![]() 9nbjC ![]() 9nbkC ![]() 9nbnC 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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| 1 |
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| Unit cell |
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Components
| #1: Protein | Mass: 23452.301 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() |
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| #2: Chemical | ChemComp-E64 / |
| #3: Water | ChemComp-HOH / |
| Has ligand of interest | Y |
| Has protein modification | Y |
-Experimental details
-Experiment
| Experiment | Method: ELECTRON CRYSTALLOGRAPHY |
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| EM experiment | Aggregation state: 3D ARRAY / 3D reconstruction method: electron crystallography |
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Sample preparation
| Component | Name: Papain-E-64 complex / Type: COMPLEX / Entity ID: #1 / Source: NATURAL |
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| Molecular weight | Experimental value: NO |
| Source (natural) | Organism: ![]() |
| Buffer solution | pH: 7 |
| Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
| Vitrification | Cryogen name: ETHANE |
-Data collection
| Experimental equipment | ![]() Model: Tecnai F20 / Image courtesy: FEI Company |
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| Microscopy | Model: TFS TALOS F200C |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 200 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: DIFFRACTION / Nominal defocus max: 10000 nm / Nominal defocus min: 10000 nm / C2 aperture diameter: 70 µm |
| Specimen holder | Cryogen: NITROGEN Specimen holder model: GATAN 626 SINGLE TILT LIQUID NITROGEN CRYO TRANSFER HOLDER Temperature (max): 100 K / Temperature (min): 100 K |
| Image recording | Average exposure time: 1.5 sec. / Electron dose: 0.045 e/Å2 / Film or detector model: DIRECT ELECTRON APOLLO (4k x 4k) |
| EM diffraction shell | Resolution: 2.3→2.4 Å / Fourier space coverage: 92.6 % / Multiplicity: 3.5 / Num. of structure factors: 1062 / Phase residual: 31.4 ° |
| EM diffraction stats | Fourier space coverage: 91.4 % / High resolution: 2.3 Å / Num. of intensities measured: 30059 / Num. of structure factors: 9018 / Phase error rejection criteria: NULL / Rmerge: 24.9 |
| Reflection | Biso Wilson estimate: 28.26 Å2 |
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Processing
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| EM 3D crystal entity | ∠α: 90 ° / ∠β: 90 ° / ∠γ: 90 ° / A: 42.18 Å / B: 49.25 Å / C: 100.69 Å / Space group name: P212121 / Space group num: 19 | |||||||||||||||||||||||||||||||||||||||||||||||||
| CTF correction | Type: NONE | |||||||||||||||||||||||||||||||||||||||||||||||||
| 3D reconstruction | Resolution: 2.3 Å / Resolution method: DIFFRACTION PATTERN/LAYERLINES / Symmetry type: 3D CRYSTAL | |||||||||||||||||||||||||||||||||||||||||||||||||
| Atomic model building | PDB-ID: 9PAP Accession code: 9PAP / Source name: PDB / Type: experimental model | |||||||||||||||||||||||||||||||||||||||||||||||||
| Refinement | Method to determine structure: MOLECULAR REPLACEMENT / Resolution: 2.3→50.34 Å / SU ML: 0.35 / Cross valid method: FREE R-VALUE / σ(F): 1.34 / Phase error: 26.25 / Stereochemistry target values: ML
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| Solvent computation | Shrinkage radii: 0.9 Å / VDW probe radii: 1.1 Å / Solvent model: FLAT BULK SOLVENT MODEL | |||||||||||||||||||||||||||||||||||||||||||||||||
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| LS refinement shell |
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MOLECULAR REPLACEMENT
United States, 3items
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