1BL8

POTASSIUM CHANNEL (KCSA) FROM STREPTOMYCES LIVIDANS

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.280 
  • R-Value Observed: 0.280 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history. 


Literature

The structure of the potassium channel: molecular basis of K+ conduction and selectivity.

Doyle, D.A., Morais Cabral, J., Pfuetzner, R.A., Kuo, A., Gulbis, J.M., Cohen, S.L., Chait, B.T., MacKinnon, R.

(1998) Science 280: 69-77

  • DOI: 10.1126/science.280.5360.69
  • Primary Citation of Related Structures:  
    1BL8

  • PubMed Abstract: 

    • The potassium channel from Streptomyces lividans is an integral membrane protein with sequence similarity to all known K+ channels, particularly in the pore region. X-ray analysis with data to 3.2 angstroms reveals that four identical subunits create an ...

    The potassium channel from Streptomyces lividans is an integral membrane protein with sequence similarity to all known K+ channels, particularly in the pore region. X-ray analysis with data to 3.2 angstroms reveals that four identical subunits create an inverted teepee, or cone, cradling the selectivity filter of the pore in its outer end. The narrow selectivity filter is only 12 angstroms long, whereas the remainder of the pore is wider and lined with hydrophobic amino acids. A large water-filled cavity and helix dipoles are positioned so as to overcome electrostatic destabilization of an ion in the pore at the center of the bilayer. Main chain carbonyl oxygen atoms from the K+ channel signature sequence line the selectivity filter, which is held open by structural constraints to coordinate K+ ions but not smaller Na+ ions. The selectivity filter contains two K+ ions about 7.5 angstroms apart. This configuration promotes ion conduction by exploiting electrostatic repulsive forces to overcome attractive forces between K+ ions and the selectivity filter. The architecture of the pore establishes the physical principles underlying selective K+ conduction.

    Organizational Affiliation: 

    Laboratory of Molecular Neurobiology and Biophysics and the Howard Hughes Medical Institute, Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.



Macromolecules
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(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
PROTEIN (POTASSIUM CHANNEL PROTEIN) A, B, C, D97Streptomyces lividansMutation(s): 1 
Gene Names: kcsA, skc1
Membrane protein
Mpstruc		Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL		Sub Group: 
Channels: Potassium, Sodium, & Proton Ion-Selective		Protein: 
KcsA Potassium channel, H+ gated
Find proteins for P0A334 (Streptomyces lividans)
Explore P0A334 
Go to UniProtKB:  P0A334
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K
Download Ideal Coordinates CCD File 
A
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.280 
  • R-Value Observed: 0.280 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 128.78α = 90
b = 68.93β = 124.63
c = 112.04γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CCP4model building
SHELXL-97model building
X-PLORrefinement
CCP4phasing
SHELXL-97phasing

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1998-07-29
    Type: Initial release
  • Version 1.1: 2007-10-16
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2017-10-04
    Changes: Refinement description