3HPL

KcsA E71H-F103A mutant in the closed state


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.2 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.220 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structural basis for the coupling between activation and inactivation gates in K(+) channels.

Cuello, L.G.Jogini, V.Cortes, D.M.Pan, A.C.Gagnon, D.G.Dalmas, O.Cordero-Morales, J.F.Chakrapani, S.Roux, B.Perozo, E.

(2010) Nature 466: 272-275

  • DOI: 10.1038/nature09136

  • PubMed Abstract: 
  • The coupled interplay between activation and inactivation gating is a functional hallmark of K(+) channels. This coupling has been experimentally demonstrated through ion interaction effects and cysteine accessibility, and is associated with a well d ...

    The coupled interplay between activation and inactivation gating is a functional hallmark of K(+) channels. This coupling has been experimentally demonstrated through ion interaction effects and cysteine accessibility, and is associated with a well defined boundary of energetically coupled residues. The structure of the K(+) channel KcsA in its fully open conformation, in addition to four other partial channel openings, richly illustrates the structural basis of activation-inactivation gating. Here, we identify the mechanistic principles by which movements on the inner bundle gate trigger conformational changes at the selectivity filter, leading to the non-conductive C-type inactivated state. Analysis of a series of KcsA open structures suggests that, as a consequence of the hinge-bending and rotation of the TM2 helix, the aromatic ring of Phe 103 tilts towards residues Thr 74 and Thr 75 in the pore-helix and towards Ile 100 in the neighbouring subunit. This allows the network of hydrogen bonds among residues Trp 67, Glu 71 and Asp 80 to destabilize the selectivity filter, allowing entry to its non-conductive conformation. Mutations at position 103 have a size-dependent effect on gating kinetics: small side-chain substitutions F103A and F103C severely impair inactivation kinetics, whereas larger side chains such as F103W have more subtle effects. This suggests that the allosteric coupling between the inner helical bundle and the selectivity filter might rely on straightforward mechanical deformation propagated through a network of steric contacts. Average interactions calculated from molecular dynamics simulations show favourable open-state interaction-energies between Phe 103 and the surrounding residues. We probed similar interactions in the Shaker K(+) channel where inactivation was impaired in the mutant I470A. We propose that side-chain rearrangements at position 103 mechanically couple activation and inactivation in KcsA and a variety of other K(+) channels.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, The University of Chicago, 929 E 57th Street, Chicago, Illinois 60637, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Antibody Fab 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 light chain
B
212N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Voltage-gated potassium channel
C
124Streptomyces lividansMutation(s): 3 
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 1 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
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.2 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.220 
  • Space Group: I 4
Unit Cell:
Length (Å)Angle (°)
a = 156.140α = 90.00
b = 156.140β = 90.00
c = 76.292γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data scaling
CNSphasing
HKL-2000data reduction
ADSCdata collection
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-06-23
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance