4MTG

Structural Basis for Ca2+ Selectivity of a Voltage-gated Calcium Channel


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.296 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.239 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis for Ca2+ selectivity of a voltage-gated calcium channel.

Tang, L.Gamal El-Din, T.M.Payandeh, J.Martinez, G.Q.Heard, T.M.Scheuer, T.Zheng, N.Catterall, W.A.

(2014) Nature 505: 56-61

  • DOI: 10.1038/nature12775
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Voltage-gated calcium (CaV) channels catalyse rapid, highly selective influx of Ca(2+) into cells despite a 70-fold higher extracellular concentration of Na(+). How CaV channels solve this fundamental biophysical problem remains unclear. Here we repo ...

    Voltage-gated calcium (CaV) channels catalyse rapid, highly selective influx of Ca(2+) into cells despite a 70-fold higher extracellular concentration of Na(+). How CaV channels solve this fundamental biophysical problem remains unclear. Here we report physiological and crystallographic analyses of a calcium selectivity filter constructed in the homotetrameric bacterial NaV channel NaVAb. Our results reveal interactions of hydrated Ca(2+) with two high-affinity Ca(2+)-binding sites followed by a third lower-affinity site that would coordinate Ca(2+) as it moves inward. At the selectivity filter entry, Site 1 is formed by four carboxyl side chains, which have a critical role in determining Ca(2+) selectivity. Four carboxyls plus four backbone carbonyls form Site 2, which is targeted by the blocking cations Cd(2+) and Mn(2+), with single occupancy. The lower-affinity Site 3 is formed by four backbone carbonyls alone, which mediate exit into the central cavity. This pore architecture suggests a conduction pathway involving transitions between two main states with one or two hydrated Ca(2+) ions bound in the selectivity filter and supports a 'knock-off' mechanism of ion permeation through a stepwise-binding process. The multi-ion selectivity filter of our CaVAb model establishes a structural framework for understanding the mechanisms of ion selectivity and conductance by vertebrate CaV channels.


    Organizational Affiliation

    1] Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA [2] Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA [3].




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Ion transport protein
A, B, C, D
237Arcobacter butzleri (strain RM4018)Mutation(s): 0 
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Channels: Calcium Ion-Selective
Protein: 
Voltage-Gated Calcium Channel (CaV) created by mutation of the NaVAb channel
Find proteins for A8EVM5 (Arcobacter butzleri (strain RM4018))
Go to UniProtKB:  A8EVM5
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
PX4
Query on PX4

Download SDF File 
Download CCD File 
A, B, C, D
1,2-DIMYRISTOYL-SN-GLYCERO-3-PHOSPHOCHOLINE
C36 H73 N O8 P
CITHEXJVPOWHKC-UUWRZZSWSA-O
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.296 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.239 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 177.250α = 90.00
b = 177.740β = 132.59
c = 131.020γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data collection
MOSFLMdata reduction
REFMACrefinement
SCALAdata scaling
PHENIXphasing
PHENIXmodel building

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-11-27
    Type: Initial release
  • Version 1.1: 2013-12-18
    Type: Database references
  • Version 1.2: 2014-01-15
    Type: Database references