4MSW

Y78 ester mutant of KcsA in high K+


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.06 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.196 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Using protein backbone mutagenesis to dissect the link between ion occupancy and C-type inactivation in K+ channels.

Matulef, K.Komarov, A.G.Costantino, C.A.Valiyaveetil, F.I.

(2013) Proc.Natl.Acad.Sci.USA 110: 17886-17891

  • DOI: 10.1073/pnas.1314356110

  • PubMed Abstract: 
  • K(+) channels distinguish K(+) from Na(+) in the selectivity filter, which consists of four ion-binding sites (S1-S4, extracellular to intracellular) that are built mainly using the carbonyl oxygens from the protein backbone. In addition to ionic dis ...

    K(+) channels distinguish K(+) from Na(+) in the selectivity filter, which consists of four ion-binding sites (S1-S4, extracellular to intracellular) that are built mainly using the carbonyl oxygens from the protein backbone. In addition to ionic discrimination, the selectivity filter regulates the flow of ions across the membrane in a gating process referred to as C-type inactivation. A characteristic of C-type inactivation is a dependence on the permeant ion, but the mechanism by which permeant ions modulate C-type inactivation is not known. To investigate, we used amide-to-ester substitutions in the protein backbone of the selectivity filter to alter ion binding at specific sites and determined the effects on inactivation. The amide-to-ester substitutions in the protein backbone were introduced using protein semisynthesis or in vivo nonsense suppression approaches. We show that an ester substitution at the S1 site in the KcsA channel does not affect inactivation whereas ester substitutions at the S2 and S3 sites dramatically reduce inactivation. We determined the structure of the KcsA S2 ester mutant and found that the ester substitution eliminates K(+) binding at the S2 site. We also show that an ester substitution at the S2 site in the KvAP channel has a similar effect of slowing inactivation. Our results link C-type inactivation to ion occupancy at the S2 site. Furthermore, they suggest that the differences in inactivation of K(+) channels in K(+) compared with Rb(+) are due to different ion occupancies at the S2 site.


    Organizational Affiliation

    Program in Chemical Biology, Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ANTIBODY FAB FRAGMENT HEAVY CHAIN
A
219N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
ANTIBODY FAB FRAGMENT LIGHT 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
103Streptomyces lividansMutation(s): 0 
Gene Names: kcsA (skc1)
Membrane protein
mpstruct
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)
Go to UniProtKB:  P0A334
Small Molecules
Ligands 2 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
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
TYF
Query on TYF
C
NON-POLYMERC9 H10 O4

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Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.06 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.196 
  • Space Group: I 4
Unit Cell:
Length (Å)Angle (°)
a = 154.530α = 90.00
b = 154.530β = 90.00
c = 75.780γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
PDB_EXTRACTdata extraction
SCALEPACKdata scaling
PHENIXrefinement
DENZOdata reduction

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: 2013-11-13
    Type: Database references
  • Version 1.2: 2017-11-15
    Type: Refinement description