7KKA

Fluoride channel Fluc-Ec2 mutant S81A with bromide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.240 
  • R-Value Observed: 0.241 

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

The fluoride permeation pathway and anion recognition in Fluc family fluoride channels.

McIlwain, B.C.Gundepudi, R.Koff, B.B.Stockbridge, R.B.

(2021) Elife 10

  • DOI: https://doi.org/10.7554/eLife.69482
  • Primary Citation of Related Structures:  
    7KK8, 7KK9, 7KKA, 7KKB, 7KKR

  • PubMed Abstract: 

    Fluc family fluoride channels protect microbes against ambient environmental fluoride by undermining the cytoplasmic accumulation of this toxic halide. These proteins are structurally idiosyncratic, and thus the permeation pathway and mechanism have no analogy in other known ion channels. Although fluoride-binding sites were identified in previous structural studies, it was not evident how these ions access aqueous solution, and the molecular determinants of anion recognition and selectivity have not been elucidated. Using x-ray crystallography, planar bilayer electrophysiology, and liposome-based assays, we identified additional binding sites along the permeation pathway. We used this information to develop an oriented system for planar lipid bilayer electrophysiology and observed anion block at one of these sites, revealing insights into the mechanism of anion recognition. We propose a permeation mechanism involving alternating occupancy of anion-binding sites that are fully assembled only as the substrate approaches.


  • Organizational Affiliation

    Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Putative fluoride ion transporter CrcB
A, B
126Escherichia coliMutation(s): 2 
Gene Names: crcBcrcB_2flc_2
Membrane Entity: Yes 
UniProt
Find proteins for Q6J5N4 (Escherichia coli)
Explore Q6J5N4 
Go to UniProtKB:  Q6J5N4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ6J5N4
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
monobody
C, D
97Homo sapiensMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
DMU
Query on DMU

Download Ideal Coordinates CCD File 
H [auth A],
K [auth B],
L [auth C]
DECYL-BETA-D-MALTOPYRANOSIDE
C22 H42 O11
WOQQAWHSKSSAGF-WXFJLFHKSA-N
BR
Query on BR

Download Ideal Coordinates CCD File 
F [auth A],
I [auth B]
BROMIDE ION
Br
CPELXLSAUQHCOX-UHFFFAOYSA-M
NA
Query on NA

Download Ideal Coordinates CCD File 
E [auth A]SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
F
Query on F

Download Ideal Coordinates CCD File 
G [auth A],
J [auth B]
FLUORIDE ION
F
KRHYYFGTRYWZRS-UHFFFAOYSA-M
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.240 
  • R-Value Observed: 0.241 
  • Space Group: P 41
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 87.391α = 90
b = 87.391β = 90
c = 141.91γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
Aimlessdata scaling
PDB_EXTRACTdata extraction
MOSFLMdata reduction
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United States--

Revision History  (Full details and data files)

  • Version 1.0: 2021-08-04
    Type: Initial release
  • Version 1.1: 2023-10-18
    Changes: Data collection, Database references, Refinement description