1SJI

Comparing skeletal and cardiac calsequestrin structures and their calcium binding: a proposed mechanism for coupled calcium binding and protein polymerization


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.192 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Comparing skeletal and cardiac calsequestrin structures and their calcium binding: a proposed mechanism for coupled calcium binding and protein polymerization.

Park, H.J.Park, I.Y.Kim, E.J.Youn, B.Fields, K.Dunker, A.K.Kang, C.H.

(2004) J.Biol.Chem. 279: 18026-18033

  • DOI: 10.1074/jbc.M311553200

  • PubMed Abstract: 
  • Calsequestrin, the major calcium storage protein of both cardiac and skeletal muscle, binds and releases large numbers of Ca(2+) ions for each contraction and relaxation cycle. Here we show that two crystal structures for skeletal and cardiac calsequ ...

    Calsequestrin, the major calcium storage protein of both cardiac and skeletal muscle, binds and releases large numbers of Ca(2+) ions for each contraction and relaxation cycle. Here we show that two crystal structures for skeletal and cardiac calsequestrin are nearly superimposable not only for their subunits but also their front-to-front-type dimers. Ca(2+) binding curves were measured using atomic absorption spectroscopy. This method enables highly accurate measurements even for Ca(2+) bound to polymerized protein. The binding curves for both skeletal and cardiac calsequestrin were complex, with binding increases that correlated with protein dimerization, tetramerization, and oligomerization. The Ca(2+) binding capacities of skeletal and cardiac calsequestrin are directly compared for the first time, with approximately 80 Ca(2+) ions bound per skeletal calsequestrin and approximately 60 Ca(2+) ions per cardiac calsequestrin, as compared with net charges for these molecules of -80 and -69, respectively. Deleting the negatively charged and disordered C-terminal 27 amino acids of cardiac calsequestrin results in a 50% reduction of its calcium binding capacity and a loss of Ca(2+)-dependent tetramer formation. Based on the crystal structures of rabbit skeletal muscle calsequestrin and canine cardiac calsequestrin, Ca(2+) binding capacity data, and previous light-scattering data, a mechanism of Ca(2+) binding coupled with polymerization is proposed.


    Organizational Affiliation

    School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-4660, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Calsequestrin, cardiac muscle isoform
A, B
350Canis lupus familiarisGene Names: CASQ2
Find proteins for P12637 (Canis lupus familiaris)
Go to Gene View: CASQ2
Go to UniProtKB:  P12637
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.192 
  • Space Group: I 4
Unit Cell:
Length (Å)Angle (°)
a = 145.188α = 90.00
b = 145.188β = 90.00
c = 99.820γ = 90.00
Software Package:
Software NamePurpose
AMoREphasing
X-PLORrefinement
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-03-15
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-11
    Type: Refinement description