Bevza А. Structural and functional basis of calix[4]arenes interaction with myosin of myometrium.

The object of investigation - structural and functional properties of myometrium actomyosin in conditions of the calixarenes action; calix[4]arenes as modulators of ATP- hydrolase activity of contractile proteins. Methods: preparative biochemistry, enzymology, biochemical kinetics, photon correlation spectroscopy, confocal microscopy and computer simulation.The aim - to study the patterns of calixarenes effects on the structural and functional properties of myosin myometrium. Calix[4]arenes, which have the ability to influence directly on ATPase activity of myosin, were first identified. It was shown that calix[4]arenes C-99 and C-97 inhibited activity of myosin subfragment-1 (head) ATPase of myometrium with similar efficiency. At the same time, calix[4]arene C-107 produced similar activating effects on the activity of ATPase of actomyosin and subfragment-1 of myosin. It is assumed that one of the targets of calixarenes effect on contractile complex is a subfragment-1 of myosin. These compounds caused a reliable increase (compared to the control) of hydrodynamic diameter of myosin subfragment-1, that allow to suppose the formation of intermolecular complex between the calixarenes and head of myosin. It was found that ATPase activity of myosin, which had been obtained from intact myocytes previously incubated with calixarene C-99, was significantly lower (almost twice) in comparison with control. The differences in subcellular distribution of myosin in uterus smooth muscle cells from rat uterus incubated with calixarene C-99 (as compared with control) were found by confocal microscopy. The molecular model of complex formation between myosin subfragment-1 and calixarenes C-99, C-97 was developed by computer simulation. Scope - organizations of biological and medical profile.