Tyrosine fluorescence in native proteins is known to be effectively quenched, whereas its emission increases upon proteins' unfolding. This suggests that tyrosine fluorescence could be exploited for probing structural rearrangements of proteins in addition to the extensively used tryptophan emission. We studied the possibility of using tyrosine fluorescence as an indicator of surfactant-induced conformational changes in albumins. It was shown that fluorescence of tyrosine residues, which are uniformly distributed all over the protein molecules, allows the detection of subtle structural rearrangements of proteins upon surfactant binding, which do not influence the properties of a single tryptophan residue buried in the inner hydrophobic region of human serum albumin. Tyrosine fluorescence properties, including its fluorescence lifetime, revealed the multistage character of surfactant binding to albumin, consistent with the data provided by other methods. The obtained results demonstrate the possibility of probing conformational changes in proteins using tyrosine photophysical parameters as indicators.
The electron-excitation energy transfer (EEET) between ionic dyes in polyelectrolyte-network polymers with a different space distribution of charged segments has been investigated. It has been established that the structure of network polymers influences the efficiency of the EEET in them mainly due to the formation of a fractal distribution of interacting molecules. It is shown that the efficiency of the EEET can be controlled by changing the number and arrangement of charged segments of polyelectrolyte networks.
Many original methods are available for studying various parameters and components of liquid water including aquatic humic substances; however, there are no remote methods for measuring organics in snow and ice. For several years, we perform a program aimed at the development of such technique.
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