Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report | Ligand Interaction | Predict Membrane 

Global Symmetry: Cyclic - C4  (3D View)
Global Stoichiometry: Homo 4-mer - A4 

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly Evidence: microscopy

Macromolecule Content

• Total Structure Weight: 151.14 kDa 
• Atom Count: 10646 
• Modelled Residue Count: 1420 
• Deposited Residue Count: 1420 
• Unique protein chains: 1

6QD4

MloK1 model from single particle analysis of 2D crystals, class 8 (intermediate conformation)

• PDB DOI: 10.2210/pdb6QD4/pdb
• EM Map EMD-4519: EMDB EMDataResource

• Classification: MEMBRANE PROTEIN
• Organism(s): Mesorhizobium japonicum MAFF 303099
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 
• Membrane Protein: Yes  PDBTMMemProtMD


• Deposited: 2018-12-31 Released: 2019-04-24 
• Deposition Author(s): Righetto, R., Biyani, N., Kowal, J., Chami, M., Stahlberg, H.
• Funding Organization(s): Swiss National Science Foundation

---

Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 5.60 Å
• Aggregation State: 2D ARRAY 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Retrieving high-resolution information from disordered 2D crystals by single-particle cryo-EM.

Righetto, R.D., Biyani, N., Kowal, J., Chami, M., Stahlberg, H.

(2019) Nat Commun 10: 1722-1722

• PubMed: 30979902 
• DOI: 10.1038/s41467-019-09661-5
• Primary Citation of Related Structures:  
  6I9D, 6IAX, 6QCY, 6QCZ, 6QD0, 6QD1, 6QD2, 6QD3, 6QD4


• PubMed 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 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.

---

Organizational Affiliation: 

Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH-4058, Basel, Switzerland. [e-mail].

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cyclic nucleotide-gated potassium channel mll3241	A, B, C, D	355	Mesorhizobium japonicum MAFF 303099	Mutation(s): 0  Gene Names: mll3241 Membrane Entity: Yes
UniProt
Find proteins for Q98GN8 (Mesorhizobium japonicum (strain LMG 29417 / CECT 9101 / MAFF 303099)) Explore Q98GN8  Go to UniProtKB:  Q98GN8

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
K	E [auth A], F [auth A]	POTASSIUM ION K NPYPAHLBTDXSSS-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 5.60 Å
• Aggregation State: 2D ARRAY 
• Reconstruction Method: SINGLE PARTICLE 

Structure Validation

Entry History & Funding Information

Deposition Data

• Deposited Date: 2018-12-31 
• Released Date: 2019-04-24 
Deposition Author(s): Righetto, R., Biyani, N., Kowal, J., Chami, M., Stahlberg, H.

---

Funding Organization	Location	Grant Number
Swiss National Science Foundation	Switzerland	205320_166164

Revision History  

• Version 1.0: 2019-04-24
  Type: Initial release