5HWX

Structural mechanisms of extracellular ion exchange and induced binding-site occlusion in the sodium-calcium exchanger NCX_Mj soaked with 2.5 mM Na+ and zero Ca2+


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.210 
  • R-Value Observed: 0.214 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Literature

Mechanism of extracellular ion exchange and binding-site occlusion in a sodium/calcium exchanger

Liao, J.Marinelli, F.Lee, C.Huang, Y.Faraldo-Gomez, J.D.Jiang, Y.

(2016) Nat Struct Mol Biol 23: 590-599

  • DOI: https://doi.org/10.1038/nsmb.3230
  • Primary Citation of Related Structures:  
    5HWX, 5HWY, 5HXC, 5HXE, 5HXH, 5HXR, 5HXS, 5HYA, 5JDF, 5JDG, 5JDH, 5JDL, 5JDM, 5JDN, 5JDQ

  • PubMed Abstract: 

    Na(+)/Ca(2+) exchangers use the Na(+) electrochemical gradient across the plasma membrane to extrude intracellular Ca(2+) and play a central role in Ca(2+) homeostasis. Here, we elucidate their mechanisms of extracellular ion recognition and exchange through a structural analysis of the exchanger from Methanococcus jannaschii (NCX_Mj) bound to Na(+), Ca(2+) or Sr(2+) in various occupancies and in an apo state. This analysis defines the binding mode and relative affinity of these ions, establishes the structural basis for the anticipated 3:1 Na(+)/Ca(2+)-exchange stoichiometry and reveals the conformational changes at the onset of the alternating-access transport mechanism. An independent analysis of the dynamics and conformational free-energy landscape of NCX_Mj in different ion-occupancy states, based on enhanced-sampling molecular dynamics simulations, demonstrates that the crystal structures reflect mechanistically relevant, interconverting conformations. These calculations also reveal the mechanism by which the outward-to-inward transition is controlled by the ion occupancy, thereby explaining the emergence of strictly coupled Na(+)/Ca(2+) antiport.


  • Organizational Affiliation

    School of Life Science and Technology, ShanghaiTech University, Shanghai, P.R. China.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
sodium,calcium exchanger301Methanocaldococcus jannaschii DSM 2661Mutation(s): 1 
Gene Names: MJ0091
Membrane Entity: Yes 
UniProt
Find proteins for Q57556 (Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440))
Explore Q57556 
Go to UniProtKB:  Q57556
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ57556
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
1PE
Query on 1PE

Download Ideal Coordinates CCD File 
F [auth A]PENTAETHYLENE GLYCOL
C10 H22 O6
JLFNLZLINWHATN-UHFFFAOYSA-N
MYS
Query on MYS

Download Ideal Coordinates CCD File 
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A]
PENTADECANE
C15 H32
YCOZIPAWZNQLMR-UHFFFAOYSA-N
PEG
Query on PEG

Download Ideal Coordinates CCD File 
E [auth A]DI(HYDROXYETHYL)ETHER
C4 H10 O3
MTHSVFCYNBDYFN-UHFFFAOYSA-N
CL
Query on CL

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D [auth A]CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
NA
Query on NA

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B [auth A],
C [auth A]
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.210 
  • R-Value Observed: 0.214 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.702α = 90
b = 72.278β = 90
c = 95.783γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data scaling
PDB_EXTRACTdata extraction
HKL-2000data reduction
SHARPphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesR01GM079179
Welch FoundationUnited StatesGrant I-1578
Harward Hughes Medical InsituteUnited Statesto Youxing Jiang
National Natural Science FoundationChinaProject 31470817
National Institutes of HealthUnited StatesDivision of Intramural Research of the National Heart, Lung and Blood Institute

Revision History  (Full details and data files)

  • Version 1.0: 2016-05-11
    Type: Initial release
  • Version 1.1: 2016-06-22
    Changes: Database references
  • Version 1.2: 2017-10-18
    Changes: Author supporting evidence, Derived calculations, Structure summary
  • Version 1.3: 2022-03-23
    Changes: Author supporting evidence, Database references
  • Version 1.4: 2023-11-08
    Changes: Data collection, Refinement description