[Study of the microstructure of the water-protein layer of spin-labeled preparations of lysozyme by the magnetic relaxation method].

Possible applications of magnetic relaxation to the studies of microstructures of water-protein layer of spin-labelled proteins and enzymes are analyzed on lyzozymes taken as an example. It is shown that the effective time of correlation of dipole-dipole interaction of the complex spin label--water proton (Tauc), as well as thermodynamic parameters Eeff. and delta Seff. reflect the local state of solvatic surrounding of lyzozyme in case of long labels. Conformation transitions of lyzozyme are revealed at the change of temperature (5--80 degrees C) and as a result of binding of a specific inhibitor NAG. It is concluded that local physico-chemical properties of water-protein matrix of lyzozyme spin-labelled preparations depend on protein conformational state.