| Abstract: | The dependence of the external and internal wide hyperfine extreme shifts of the ESR spectra on temperature and viscosity for spin-probes in solution of BSA was studied. Seven homologous spin-probes of carboline and benzocarboline derivatives were used. The obtained dependences are a consequence of the involvement of the spin-probe in two types of rotation: an anisotropic fast reorientation with tau > 10(-9) s with respect to a macromolecule and the isotropic one with tau > 10(-8) s due to rotation of the macromolecule itself. It was shown, that extrapolation values of a separation between hyperfine extreme do not reflect the degree of the immediate spin-probe environment polarity, but are determined by the hyperfine tenzor partial averaging as a result of the rapid anisotropic reorientation of the spin-probe. All spin-probes used were shown to be bound by the BSA molecule in the near vicinity of the tryptophan residue. The rotation correlation time of the BSA molecule was determined to be equal to 40 ns. |
