Thermodynamics of calmodulin binding to cardiac and skeletal muscle ryanodine receptor ion channels

Gerhard Meissner, Daniel A. Pasek, Naohiro Yamaguchi, Srinivas Ramachandran, Nikolay V. Dokholyan, Ashutosh Tripathy

Research output: Contribution to journalArticle

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Abstract

The skeletal muscle (RyR1) and cardiac muscle (RyR2) ryanodine receptor calcium release channels contain a single, conserved calmodulin (CaM) binding domain, yet are differentially regulated by CaM. Here, we report that high-affinity [ 35S]CaM binding to RyR1 is driven by favorable enthalpic and entropic contributions at Ca 2+ concentrations from <0.01 to 100 μM. At 0.15 μMCa 2+, [ 35S]CaM bound to RyR2 with decreased affinity and binding enthalpy compared with RyR1. The rates of [ 35S]CaM dissociation from RyR1 increased as the temperature was raised, whereas at 0.15 μMCa 2+ the rate from RyR2 was little affected. The results suggest major differences in the energetics of CaM binding to and dissociation from RyR1 and RyR2.

Original languageEnglish (US)
Pages (from-to)207-211
Number of pages5
JournalProteins: Structure, Function and Bioinformatics
Volume74
Issue number1
DOIs
StatePublished - Jan 1 2009

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All Science Journal Classification (ASJC) codes

  • Structural Biology
  • Biochemistry
  • Molecular Biology

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