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Journal of Biomolecular NMR

, Volume 54, Issue 1, pp 115–121 | Cite as

NMR structure note: solution structure of Ca2+ binding domain 2B of the third isoform of the Na+/Ca2+ exchanger

  • Vincent Breukels
  • Wouter G. Touw
  • Geerten W. Vuister
NMR structure note

Biological context

The Na+/Ca2+ exchanger (NCX) is an omnipresent plasma membrane protein that catalyzes the removal of intracellular Ca2+ for the uptake of Na+ [see for review (Lytton 2007)]. Mammals express three isoforms, denoted as NCX1, NCX2, or NCX3, of which isoforms 1 and 3 also display alternative splicing. The exchanger is activated by allosteric Ca2+ binding to Ca2+ binding domains 1 and 2 (CBD1 and CBD2) located in the large cytosolic loop between transmembrane helix 5 and 6. CBD1 binds four Ca2+ ions, irrespective of the isoform and is considered the primary Ca2+ sensor. The number of Ca2+ ions that bind to CBD2 depends on the isoform and splice variant. It is hypothesized that the number of binding sites determines the ability of the exchanger to overcome the Na+ dependent inactivation (Hilge et al. 2009) and that Mg2+ binding plays a modulating role (Boyman et al. 2009; Breukels et al. 2011).

NCX1 is thus far the best-studied isoform and solution or X-ray structures of...

Keywords

Resonance Assignment Isothermal Titration Calorimetry Backbone Dynamic Alignment Medium Side Chain Chemical Shift 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Abbreviations

CBD2

Ca2+ binding domain 2

HEPES

4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid

KD

Macroscopic dissociation constant

ITC

Isothermal titration calorimetry

NCX3

Na+/Ca2+ exchanger isoform 3

NOE

Nuclear Overhauser effect

OD600

Optical density at 600 nm

RDC

Residual dipolar coupling

r.m.s.

Root mean square

r.m.s.d.

Root mean square deviation

SDS-PAGE

Sodium dodecyl sulfate polyacrylamide gel electrophoresis

Notes

Acknowledgments

We thank Jurgen Doreleijers for assistance with Xplor-NIH and iCing, Gjalt van Rutten for support with using the HPC Cloud infrastructure at BitBrains. This work was supported by grants from the Netherlands Organization for Scientific Research (NWO): 700.55.443 and 700.57.101.

Supplementary material

10858_2012_9654_MOESM1_ESM.pdf (3.2 mb)
Supplementary material 1 (PDF 3261 kb)

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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Vincent Breukels
    • 1
    • 2
  • Wouter G. Touw
    • 1
  • Geerten W. Vuister
    • 3
  1. 1.Institute for Molecules and MaterialsRadboud University NijmegenNijmegenThe Netherlands
  2. 2.Department of RadiologyRadboud University Nijmegen Medical CentreNijmegenThe Netherlands
  3. 3.Department of BiochemistryUniversity of LeicesterLeicesterUK

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