Structural basis for the negative allostery between Ca2+- and Mg2+-binding in the intracellular Ca2+-receptor calbindin D(9k)

M. Andersson, I. Ivarsson, L. Anders Svensson, A. Malmendal, S. Linse*, S. Forsén

*Corresponding author

Publikation: Bidrag til tidsskriftTidsskriftartikelpeer review

Abstract

The three-dimensional structures of the magnesium- and manganese-bound forms of calbindin D(9k) were determined to 1.6 Å and 1.9 Å resolution, respectively, using X-ray crystallography. These two structures are nearly identical but deviate significantly from both the calcium bound form and the metal ion-free (apo) form. The largest structural differences are seen in the C-terminal EF-hand, and involve changes in both metal ion coordination and helix packing. The N-terminal calcium binding site is not occupied by any metal ion in the magnesium and manganese structures, and shows little structural deviation from the apo and calcium bound forms.1H-NMR and UV spectroscopic studies at physiological ion concentrations show that the C- terminal site of the protein is significantly populated by magnesium at resting cell calcium levels, and that there is a negative allosteric interaction between magnesium and calcium binding. Calcium binding was found to occur with positive cooperativity at physiological magnesium concentration.
OriginalsprogEngelsk
TidsskriftProtein Science
Vol/bind6
Udgave nummer6
Sider (fra-til)1139-1147
ISSN0961-8368
DOI
StatusUdgivet - 1997
Udgivet eksterntJa

Bibliografisk note

This article has been found as a ’Free Version’ from the Publisher on June 23 2020. When access to the article closes, please notify rucforsk@ruc.dk

Emneord

  • Allosteric interaction
  • Calcium-binding protein
  • Cooperativity
  • EF-hand protein
  • Magnesium binding
  • Nuclear magnetic resonance
  • X-ray crystallography

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