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Yorodumi- PDB-6iax: MloK1 model from single particle analysis of 2D crystals, class 1... -
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-Basic information
Entry | Database: PDB / ID: 6iax | ||||||
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Title | MloK1 model from single particle analysis of 2D crystals, class 1 (extended conformation) | ||||||
Components | Cyclic nucleotide-gated potassium channel mll3241 | ||||||
Keywords | MEMBRANE PROTEIN / Voltage-gated potassium channel / Cyclic nucleotide-binding domain / ion channel / ion transport | ||||||
Function / homology | Function and homology information potassium channel activity / cAMP binding / protein-containing complex binding / identical protein binding / plasma membrane Similarity search - Function | ||||||
Biological species | Mesorhizobium japonicum | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 5.2 Å | ||||||
Authors | Righetto, R. / Biyani, N. / Kowal, J. / Chami, M. / Stahlberg, H. | ||||||
Funding support | Switzerland, 1items
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Citation | Journal: Nat Commun / Year: 2019 Title: Retrieving high-resolution information from disordered 2D crystals by single-particle cryo-EM. Authors: Ricardo D Righetto / Nikhil Biyani / Julia Kowal / Mohamed Chami / Henning Stahlberg / Abstract: Electron crystallography can reveal the structure of membrane proteins within 2D crystals under close-to-native conditions. High-resolution structural information can only be reached if crystals are ...Electron crystallography can reveal the structure of membrane proteins within 2D crystals under close-to-native conditions. High-resolution structural information can only be reached if crystals are perfectly flat and highly ordered. In practice, such crystals are difficult to obtain. Available image unbending algorithms correct for disorder, but only perform well on images of non-tilted, flat crystals, while out-of-plane distortions are not addressed. Here, we present an approach that employs single-particle refinement procedures to locally unbend crystals in 3D. With this method, density maps of the MloK1 potassium channel with a resolution of 4 Å were obtained from images of 2D crystals that do not diffract beyond 10 Å. Furthermore, 3D classification allowed multiple structures to be resolved, revealing a series of MloK1 conformations within a single 2D crystal. This conformational heterogeneity explains the poor diffraction observed and is related to channel function. The approach is implemented in the FOCUS package. | ||||||
History |
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-Structure visualization
Movie |
Movie viewer |
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Structure viewer | Molecule: MolmilJmol/JSmol |
-Downloads & links
-Download
PDBx/mmCIF format | 6iax.cif.gz | 446.2 KB | Display | PDBx/mmCIF format |
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PDB format | pdb6iax.ent.gz | 375.4 KB | Display | PDB format |
PDBx/mmJSON format | 6iax.json.gz | Tree view | PDBx/mmJSON format | |
Others | Other downloads |
-Validation report
Summary document | 6iax_validation.pdf.gz | 1.3 MB | Display | wwPDB validaton report |
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Full document | 6iax_full_validation.pdf.gz | 1.3 MB | Display | |
Data in XML | 6iax_validation.xml.gz | 43.8 KB | Display | |
Data in CIF | 6iax_validation.cif.gz | 63.2 KB | Display | |
Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/ia/6iax ftp://data.pdbj.org/pub/pdb/validation_reports/ia/6iax | HTTPS FTP |
-Related structure data
Related structure data | 4441MC 4432C 4439C 4513C 4514C 4515C 4516C 4517C 4518C 4519C 6i9dC 6qcyC 6qczC 6qd0C 6qd1C 6qd2C 6qd3C 6qd4C C: citing same article (ref.) M: map data used to model this data |
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Similar structure data |
-Links
-Assembly
Deposited unit |
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1 |
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-Components
#1: Protein | Mass: 37766.297 Da / Num. of mol.: 4 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Mesorhizobium japonicum (strain LMG 29417 / CECT 9101 / MAFF 303099) (bacteria) Strain: LMG 29417 / CECT 9101 / MAFF 303099 / Gene: mll3241 / Production host: Escherichia coli BL21(DE3) (bacteria) / References: UniProt: Q98GN8 #2: Chemical | |
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-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: 2D ARRAY / 3D reconstruction method: single particle reconstruction |
-Sample preparation
Component | Name: MloK1 potassium channel in lipidic bilayer of 2D crystals Type: COMPLEX / Entity ID: #1 / Source: RECOMBINANT |
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Molecular weight | Value: 0.16 MDa / Experimental value: YES |
Source (natural) | Organism: Mesorhizobium loti MAFF303099 (bacteria) |
Source (recombinant) | Organism: Escherichia coli BL21(DE3) (bacteria) |
Buffer solution | pH: 7.6 Details: 20 mM KCl, 20 mM Tris-HCl pH 7.6, 1 mM BaCl2, 1 mM EDTA, 0.2 mM cAMP |
Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Vitrification | Cryogen name: ETHANE |
-Electron microscopy imaging
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: OTHER |
Electron lens | Mode: BRIGHT FIELD / Nominal magnification: 50000 X / Nominal defocus max: 4300 nm / Nominal defocus min: 750 nm / Cs: 2.7 mm |
Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
Image recording | Average exposure time: 16 sec. / Electron dose: 45 e/Å2 / Detector mode: COUNTING / Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Num. of real images: 270 Details: The dataset of 346 movies recorded and processed for Kowal et al. (2018) 2 was employed. As reported, the data were collected on an FEI Titan Krios TEM equipped with a Gatan K2 DED. Total ...Details: The dataset of 346 movies recorded and processed for Kowal et al. (2018) 2 was employed. As reported, the data were collected on an FEI Titan Krios TEM equipped with a Gatan K2 DED. Total dose: 40 e-/A^2 distributed over 40 movie frames. Pixel size: 1.3 A on the sample level (counting mode). Nominal tilt range: -55 to +55 degrees. |
-Processing
EM software |
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CTF correction | Details: The defocus at the center of each particle box was estimated based on the tilt geometry. Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 231688 Details: The particle positions were given by the cross-correlation profile generated by the classical unbending algorithm. | ||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 5.2 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 27849 / Algorithm: FOURIER SPACE Details: Resolution estimated based on FSC between spherically-masked half-maps with a soft edge, with the FSC normalized to an expected volume corresponding to a molecular weight of 160 kDa. Num. of class averages: 1 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||
Atomic model building | Protocol: FLEXIBLE FIT Details: The consensus model was flexibily fit in to the EM map of this class using Normal Mode Analysis with iMODFIT, and then real-space refined using PHENIX. | ||||||||||||||||||||||||||||||||||||
Atomic model building | PDB-ID: 6I9D Accession code: 6I9D / Source name: PDB / Type: experimental model |