Binding of nucleotides at the active site modulates the local and global conformation of myosin in muscle fibres

D. Lrinczy, N. Hartvig, N. Farkas, J. Belagyi

Research output: Conference article

7 Citations (Scopus)

Abstract

Differential scanning calorimetry and electron paramagnetic resonance experiments were performed on glycerinated muscle fibres to study the effect of the binding of nucleotides (ADP and AMP·PNP) to myosin. The thermal unfolding of muscle fibres showed three discrete domain regions with thermal stabilities of 52.2, 58.8 and 67.8°C. AMP·PNP markedly affected the transitions, implying the strong interaction between AMP·PNP and catalytic domain, and partial dissociation of heads from actin. ADP produced only small changes in transition temperatures. Spectrum deconvolution performed on isothiocyanate-labelled fibres in AMP·PNP-state resulted in two populations; 50% of labels was highly ordered with respect to fibre axis, whereas the other 50% of labels was randomly oriented. The conformation of the myosin heads which showed high degree of order were in the strongly binding ADP-state, the heads being attached to actin differ from those of heads in rigor. The results support the suggestion that the attached heads in strongly binding state to actin might have different local conformations.

Original languageEnglish
Pages (from-to)351-358
Number of pages8
JournalJournal of Thermal Analysis and Calorimetry
Volume65
Issue number2
DOIs
Publication statusPublished - okt. 1 2001
Event8th Conference on Calorimetry and Thermal Analysis (CCTA 8) - Zakopane, Poland
Duration: szept. 3 2000szept. 8 2000

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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