4MVQ

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.40 Å
  • R-Value Free: 0.313 
  • R-Value Work: 0.280 
  • R-Value Observed: 0.281 

wwPDB Validation 3D Report Full Report


This is version 1.3 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:  
    4MS2, 4MTO, 4MTF, 4MTG, 4MVU, 4MW8, 4MVZ, 4MVM, 4MVO, 4MVQ

  • 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

    Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Ion transport proteinABCD237Arcobacter butzleri RM4018Mutation(s): 0 
Gene Names: Abu_1752
Find proteins for A8EVM5 (Arcobacter butzleri (strain RM4018))
Explore A8EVM5 
Go to UniProtKB:  A8EVM5
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PX4
Query on PX4

Download CCD File 
A, B, C, D
1,2-DIMYRISTOYL-SN-GLYCERO-3-PHOSPHOCHOLINE
C36 H73 N O8 P
CITHEXJVPOWHKC-UUWRZZSWSA-O
 Ligand Interaction
CA
Query on CA

Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.40 Å
  • R-Value Free: 0.313 
  • R-Value Work: 0.280 
  • R-Value Observed: 0.281 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 177.78α = 90
b = 177.725β = 132.79
c = 130.82γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHENIXmodel building
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
PHENIXphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-11-27
    Type: Initial release
  • Version 1.1: 2013-12-18
    Changes: Database references
  • Version 1.2: 2014-01-15
    Changes: Database references
  • Version 1.3: 2014-11-12
    Changes: Structure summary