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Influence of Mg 2+ and Ca 2+ bound to 1,5‐IAEDANS‐labeled phosphorylated and dephosphorylated heavy meromyosin complexed with F‐actin on polarized fluorescence of the fluorophore
Author(s) -
Borovikov Yu.S.,
Wrotek M.,
Aksenova N.B.,
Lebedeva N.N.,
Kakol I.
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)80329-0
Subject(s) - heavy meromyosin , chemistry , fluorescence , myosin , fluorescence anisotropy , phosphorylation , actin , fluorophore , divalent , biophysics , meromyosin , myosin light chain kinase , biochemistry , myosin head , organic chemistry , optics , physics , membrane , biology
Dephosphorylated and phosphorylated heavy meromyosin, fluorescently labeled with 1,5‐IAEDANS attached at the SH 1 group, was introduced into myosin‐free ghost fibres and the polarized fluorescence of the bound label was measured. The results depended on whether the divalent cation binding sites on heavy meromyosin were saturated with Mg 2+ or Ca 2+ . The calculated angles of absorption and emission dipoles and the amount of random fluorophores were significantly changed, indicating that the random mobility and orientation of the fluorophores of phosphorylated and dephosphorylated heavy meromyosin heads complexed with F‐actin in the ghost fibre depend on saturation of heavy meromyosin with Ca 2+ or Mg 2+ . The presence of bound Ca 2+ has an opposite effect on the polarized fluorescence of phosphorylated and dephosphorylated 1,5‐IAEDANS‐heavy meromyosin.