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The rotational motions of the actin from rabbit skeletal muscle and from chicken gizzard smooth muscle were measured by conventional and saturation transfer electron paramagnetic resonance (EPR) spectroscopy using maleimide spin-label rigidly bound at Cys-374. The conventional EPR spectra indicate a slight difference in the polarity of the environment of(More)
Temperature dependence of the fluorescence intensity and anisotropy decay of N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)ethylenediamine attached to Cys374 of actin monomer was investigated to characterize conformational differences between Ca- and Mg-G-actin. The fluorescence lifetime is longer in Mg-G-actin than that in Ca-G-actin in the temperature range of(More)
In this study, we analysed the ethanol-induced long term cell injury on a general cell model (Sp2/0-Ag14 cell line). Cells were incubated in 1, 5, 10, 15 and 20% of ethanol (EtOH) for 5 min. After washing cell viability was tested by the Trypan Blue exclusion test in 5, 60 min, 4 and 24 h after EtOH exposure. Free radicals were monitored every 30 min by(More)
The interactions of chromium(VI) with the plasma membranes of chromium-sensitive (chr-51S) and chromium-tolerant (chr1-66T) mutants and their parental strain (6chr(+)) of a Schizosaccharomyces pombe strain were studied by electron paramagnetic resonance (EPR) spectroscopy. 5-doxylstearic acid (5-SASL) and 3-doxylbutyric acid (HO-185) spin probes were used(More)
The principal aim of this investigation was to study the change of the protein flexibility and/or conformational properties of actin filaments upon the replacement of Ca2+ by Mg2+. The temperature dependence of the fluorescence lifetime and the anisotropy decay of N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)ethylenediamine (IAEDANS) attached covalently to the(More)
The temperature profile of the fluorescence resonance energy transfer efficiency normalized by the fluorescence quantum yield of the donor in the presence of acceptor, f', was measured in a way allowing the independent investigation of (i) the strength of interaction between the adjacent protomers (intermonomer flexibility) and (ii) the flexibility of the(More)
Experiments were performed on glycerol-extracted muscle fibres prepared from psoas muscle of rabbit in the presence of hydroxyl free radical generating system. Short irradiation of spin-labelled muscle fibres by UV light showed the interaction of probe molecules with oxygen free radicals. The intensity of the EPR signal from maleimide or isothiocyanate spin(More)
Conformational and dynamic properties of actin filaments polymerized from ATP- or ADP-actin monomers were compared by using fluorescence spectroscopic methods. The fluorescence intensity of IAEDANS attached to the Cys(374) residue of actin was smaller in filaments from ADP-actin than in filaments from ATP-actin monomers, which reflected a nucleotide-induced(More)
Rotational dynamics of actin spin-labelled with maleimide probes at the reactive thiol Cys-374 were studied. Replacement of the bound nucleotide by Br8ATP in G-actin and Br8ADP in F-actin causes significant increase of the rotational correlation time of the spin probe, indicating reduced motion in both G and F-actin. The orientation dependence of the(More)
The effect of the replacement of ATP with ADP on the conformational and dynamic properties of the actin monomer was investigated, by means of electron paramagnetic resonance (EPR) and fluorescence spectroscopic methods. The measurement of the ATP concentration during these experiments provided the opportunity to estimate the time dependence of(More)