4LBE

Structure of KcsA with R122A mutation


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.751 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.167 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Molecular interactions involved in proton-dependent gating in KcsA potassium channels.

Posson, D.J.Thompson, A.N.McCoy, J.G.Nimigean, C.M.

(2013) J.Gen.Physiol. 142: 613-624

  • DOI: 10.1085/jgp.201311057
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The bacterial potassium channel KcsA is gated open by the binding of protons to amino acids on the intracellular side of the channel. We have identified, via channel mutagenesis and x-ray crystallography, two pH-sensing amino acids and a set of nearb ...

    The bacterial potassium channel KcsA is gated open by the binding of protons to amino acids on the intracellular side of the channel. We have identified, via channel mutagenesis and x-ray crystallography, two pH-sensing amino acids and a set of nearby residues involved in molecular interactions that influence gating. We found that the minimal mutation of one histidine (H25) and one glutamate (E118) near the cytoplasmic gate completely abolished pH-dependent gating. Mutation of nearby residues either alone or in pairs altered the channel's response to pH. In addition, mutations of certain pairs of residues dramatically increased the energy barriers between the closed and open states. We proposed a Monod-Wyman-Changeux model for proton binding and pH-dependent gating in KcsA, where H25 is a "strong" sensor displaying a large shift in pKa between closed and open states, and E118 is a "weak" pH sensor. Modifying model parameters that are involved in either the intrinsic gating equilibrium or the pKa values of the pH-sensing residues was sufficient to capture the effects of all mutations.


    Organizational Affiliation

    Department of Anesthesiology, 2 Department of Physiology and Biophysics, and 3 Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Fab light chain
A
219N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Fab heavy chain
B
212N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
pH-gated potassium channel KcsA
C
130Streptomyces lividansMutation(s): 1 
Gene Names: kcsA (skc1)
Find proteins for P0A334 (Streptomyces lividans)
Go to UniProtKB:  P0A334
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

Download SDF File 
Download CCD File 
C
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
DGA
Query on DGA

Download SDF File 
Download CCD File 
C
DIACYL GLYCEROL
C39 H76 O5
UHUSDOQQWJGJQS-QNGWXLTQSA-N
 Ligand Interaction
F09
Query on F09

Download SDF File 
Download CCD File 
A
NONAN-1-OL
C9 H20 O
ZWRUINPWMLAQRD-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.751 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.167 
  • Space Group: I 4
Unit Cell:
Length (Å)Angle (°)
a = 155.938α = 90.00
b = 155.938β = 90.00
c = 75.814γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
DENZOdata reduction
HKL-2000data collection
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-10-30
    Type: Initial release
  • Version 1.1: 2014-02-05
    Type: Database references
  • Version 1.2: 2014-04-02
    Type: Other
  • Version 1.3: 2017-11-15
    Type: Refinement description