-transparent.png){kind=logo}
Changes in anisotropy of tryptophan fluorescence and in birefringence of actin filaments induced by the binding to actin of heavy meromyosin (HMM), both containing DTNB light chains and devoid of them, were found in rabbit muscle fibres free of myosin, troponin, and tropomyosin. Ca2+ was shown to affect the pattern of changes in tryptophan fluorescence anisotropy and birefringence of actin filament at the moment of HMM interaction with actin, providing HMM contains DTNB light chains. Anisotropy of tryptophan fluorescence and birefringence of actin filaments rises in the absence of Ca2+ (pCa greater than or equal to 7), while in its presence (pCa less than or equal to 6) these values drop down. Furthermore, these changes become cooperative when Ca2+ concentration increases from pCa = 7 to pCa = 6. It was shown that the binding of HMM devoid of DTNB light chains to F-actin decreases tryptophan fluorescence anisotropy and birefrigence of actin filaments, regardless of Ca2+ concentration. Ca2+-dependent structural changes of F-actin induced by interaction of heads of myosin molecules with actin are assumed to be of great importance in regulation of muscle contraction of vertebrate skeletal muscles.
Iu S Borovikov, and
E A Karandashov
May 1982,
Tsitologiia,
Iu S Borovikov, and
E A Karandashov
November 1984,
Tsitologiia,
Iu S Borovikov, and
E A Karandashov
October 1978,
Tsitologiia,
Iu S Borovikov, and
E A Karandashov
December 1978,
Tsitologiia,
Iu S Borovikov, and
E A Karandashov
November 1976,
Tsitologiia,
Iu S Borovikov, and
E A Karandashov
December 1976,
Tsitologiia,
Iu S Borovikov, and
E A Karandashov
July 1998,
FEBS letters,
Iu S Borovikov, and
E A Karandashov
May 1976,
Journal of biochemistry,
Iu S Borovikov, and
E A Karandashov
August 1974,
Tsitologiia,
Iu S Borovikov, and
E A Karandashov
October 1985,
General physiology and biophysics,
