Influence of Mg2+ and Ca2+ bound to 1,5‐IAEDANS‐labeled phosphorylated and dephosphorylated heavy meromyosin complexed with F‐actin on polarized fluorescence of the fluorophore

FEBS Letters

Aksenova, N.B.²  Kakol, I.²  Lebedeva, N.N.²  Borovikov, Yu.S.²  Wrotek, M.¹ 

[1] Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warszawa, Poland;Group of Cell Motility, Institute of Cytology, Academy of Sciences of the USSR, 4 Tikhoretski ave., Leningrad 194-064, USSR

关键词: Heavy meromyosin;    Polarized fluorescence;    Ghost fiber;    Ca2+ regulation;   

DOI  :  10.1016/0014-5793(87)80329-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Dephosphorylated and phosphorylated heavy meromyosin, fluorescently labeled with 1,5-IAEDANS attached at the SH₁ 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 Mg²⁺ or Ca²⁺. 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 Ca²⁺ or Mg²⁺. The presence of bound Ca²⁺ has an opposite effect on the polarized fluorescence of phosphorylated and dephosphorylated 1,5-IAEDANS-heavy meromyosin.

【 授权许可】

Unknown