4UUJ

POTASSIUM CHANNEL KCSA-FAB WITH TETRAHEXYLAMMONIUM


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.194 

Starting Model: experimental
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This is version 1.3 of the entry. See complete history


Literature

Structures of Kcsa in Complex with Symmetrical Quaternary Ammonium Compounds Reveal a Hydrophobic Binding Site.

Lenaeus, M.J.Burdette, D.Wagner, T.Focia, P.J.Gross, A.

(2014) Biochemistry 53: 5365

  • DOI: https://doi.org/10.1021/bi500525s
  • Primary Citation of Related Structures:  
    2JK5, 2W0F, 4UUJ

  • PubMed Abstract: 

    Potassium channels allow for the passive movement of potassium ions across the cell membrane and are instrumental in controlling the membrane potential in all cell types. Quaternary ammonium (QA) compounds block potassium channels and have long been used to study the functional and structural properties of these channels. Here we describe the interaction between three symmetrical hydrophobic QAs and the prokaryotic potassium channel KcsA. The structures demonstrate the presence of a hydrophobic pocket between the inner helices of KcsA and provide insight into the binding site and blocking mechanism of hydrophobic QAs. The structures also reveal a structurally hidden pathway between the central cavity and the outside membrane environment reminiscent of the lateral fenestration observed in sodium channels that can be accessed through small conformational changes in the pore wall. We propose that the hydrophobic binding pocket stabilizes the alkyl chains of long-chain QA molecules and may play a key role in hydrophobic drug binding in general.


  • Organizational Affiliation

    Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School , 303 East Chicago Avenue, Chicago, Illinois 60611, United States.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ANTIBODY FAB FRAGMENT LIGHT CHAIN219Mus musculusMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
ANTIBODY FAB FRAGMENT HEAVY CHAIN212Mus musculusMutation(s): 0 
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  • Reference Sequence
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
VOLTAGE-GATED POTASSIUM CHANNEL KCSA111Streptomyces lividansMutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for P0A334 (Streptomyces lividans)
Explore P0A334 
Go to UniProtKB:  P0A334
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A334
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 7 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
DGA
Query on DGA

Download Ideal Coordinates CCD File 
J [auth C]DIACYL GLYCEROL
C39 H76 O5
UHUSDOQQWJGJQS-QNGWXLTQSA-N
XA7
Query on XA7

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L [auth C],
M [auth C]
TETRAHEXYL AMMONNIUM
C24 H52 N
DTIFFPXSSXFQCJ-UHFFFAOYSA-N
F09
Query on F09

Download Ideal Coordinates CCD File 
D [auth A],
O [auth C],
P [auth C],
Q [auth C]
NONAN-1-OL
C9 H20 O
ZWRUINPWMLAQRD-UHFFFAOYSA-N
IND
Query on IND

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E [auth B]INDOLE
C8 H7 N
SIKJAQJRHWYJAI-UHFFFAOYSA-N
PO4
Query on PO4

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N [auth C]PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
CO
Query on CO

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K [auth C]COBALT (II) ION
Co
XLJKHNWPARRRJB-UHFFFAOYSA-N
K
Query on K

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F [auth C],
G [auth C],
H [auth C],
I [auth C]
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.194 
  • Space Group: I 4
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 154.615α = 90
b = 154.615β = 90
c = 75.953γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
XSCALEdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-08-27
    Type: Initial release
  • Version 1.1: 2014-09-03
    Changes: Database references
  • Version 1.2: 2024-01-10
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description
  • Version 1.3: 2024-10-16
    Changes: Structure summary