Biological Assembly 1  

Global Symmetry: Cyclic - C5  (3D View)
Global Stoichiometry: Homo 5-mer - A5 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: light scattering

Macromolecule Content

• Total Structure Weight: 204.01 kDa 
• Atom Count: 13,885 
• Modelled Residue Count: 1,690 
• Deposited Residue Count: 1,740 
• Unique protein chains: 1

 6N28

BEST1 calcium-bound open state

• PDB DOI:  https://doi.org/10.2210/pdb6N28/pdb
• EM Map EMD-9326: EMDB EMDataResource

• Classification: MEMBRANE PROTEIN
• Organism(s): Gallus gallus
• Expression System: Komagataella pastoris
• Mutation(s): No 


• Deposited: 2018-11-12 Released: 2019-01-23 
• Deposition Author(s): Miller, A.N., Vaisey, G., Long, S.B.
• Funding Organization(s): National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS), National Institutes of Health/National Cancer Institute (NIH/NCI)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 2.90 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Molecular mechanisms of gating in the calcium-activated chloride channel bestrophin.

Miller, A.N., Vaisey, G., Long, S.B.

(2019) Elife 8

• PubMed: 30628889 
• DOI: https://doi.org/10.7554/eLife.43231
• Primary Citation of Related Structures:  
  6N23, 6N24, 6N25, 6N26, 6N27, 6N28


• PubMed Abstract: 
  

Bestrophin (BEST1-4) ligand-gated chloride (Cl ^- ) channels are activated by calcium (Ca ²⁺ ). Mutation of BEST1 causes retinal disease. Partly because bestrophin channels have no sequence or structural similarity to other ion channels, the molecular mechanisms underlying gating are unknown. Here, we present a series of cryo-electron microscopy structures of chicken BEST1, determined at 3.1 Å resolution or better, that represent the channel's principal gating states. Unlike other channels, opening of the pore is due to the repositioning of tethered pore-lining helices within a surrounding protein shell that dramatically widens a neck of the pore through a concertina of amino acid rearrangements. The neck serves as both the activation and the inactivation gate. Ca ²⁺ binding instigates opening of the neck through allosteric means whereas inactivation peptide binding induces closing. An aperture within the otherwise wide pore controls anion permeability. The studies define a new molecular paradigm for gating among ligand-gated ion channels.

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Organizational Affiliation: 

Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Bestrophin homolog	A, B, C, D, E	348	Gallus gallus	Mutation(s): 0  Gene Names: BEST1

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA	F [auth A], G [auth B], H [auth C], I [auth D], J [auth E]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 2.90 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
MODEL REFINEMENT	PHENIX	1.13
RECONSTRUCTION	RELION	2.1

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2019-01-23 
Deposition Author(s): Miller, A.N., Vaisey, G., Long, S.B.

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Funding Organization	Location	Grant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)	United States	GM110396
National Institutes of Health/National Cancer Institute (NIH/NCI)	United States	P30 CA008748

Revision History  

• Version 1.0: 2019-01-23
  Type: Initial release
  
• Version 1.1: 2019-12-04
  Changes: Author supporting evidence
• Version 1.2: 2019-12-18
  Changes: Other