4EI2

Crystal Structures of MthK RCK gating ring bound to Barium


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.108 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.209 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal Structure of a Ba(2+)-Bound Gating Ring Reveals Elementary Steps in RCK Domain Activation.

Smith, F.J.Pau, V.P.Cingolani, G.Rothberg, B.S.

(2012) Structure 20: 2038-2047

  • DOI: 10.1016/j.str.2012.09.014

  • PubMed Abstract: 
  • RCK domains control activity of a variety of K(+) channels and transporters through binding of cytoplasmic ligands. To gain insight toward mechanisms of RCK domain activation, we solved the structure of the RCK domain from the Ca(2+)-gated K(+) chann ...

    RCK domains control activity of a variety of K(+) channels and transporters through binding of cytoplasmic ligands. To gain insight toward mechanisms of RCK domain activation, we solved the structure of the RCK domain from the Ca(2+)-gated K(+) channel, MthK, bound with Ba(2+), at 3.1 Å resolution. The Ba(2+)-bound RCK domain was assembled as an octameric gating ring, as observed in structures of the full-length MthK channel, and shows Ba(2+) bound at several positions. One of the Ba(2+) sites, termed C1, overlaps with a known Ca(2+)-activation site, determined by residues D184 and E210. Functionally, Ba(2+) can activate reconstituted MthK channels as observed in electrophysiological recordings, whereas Mg(2+) (up to 100 mM) was ineffective. Ba(2+) activation was abolished by the mutation D184N, suggesting that Ba(2+) activates primarily through the C1 site. Our results suggest a working hypothesis for a sequence of ligand-dependent conformational changes that may underlie RCK domain activation and channel gating.


    Organizational Affiliation

    Department of Biochemistry, Temple University School of Medicine, 3400 N. Broad Street, Philadelphia, PA 19140, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Calcium-gated potassium channel mthK
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P
242Methanothermobacter thermautotrophicus (strain ATCC 29096 / DSM 1053 / JCM 10044 / NBRC 100330 / Delta H)Mutation(s): 0 
Gene Names: mthK
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Channels: Potassium, Sodium, & Proton Ion-Selective
Protein: 
MthK Potassium channel, Ca++ gated
Find proteins for O27564 (Methanothermobacter thermautotrophicus (strain ATCC 29096 / DSM 1053 / JCM 10044 / NBRC 100330 / Delta H))
Go to UniProtKB:  O27564
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
BA
Query on BA

Download SDF File 
Download CCD File 
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P
BARIUM ION
Ba
XDFCIPNJCBUZJN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.108 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.209 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 110.045α = 90.00
b = 136.419β = 90.00
c = 498.427γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
HKL-2000data scaling
HKL-2000data reduction
ADSCdata collection
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-12-19
    Type: Initial release
  • Version 1.1: 2014-04-16
    Type: Other