[Possible use of ultraviolet fluorescence for detecting protein conformational transitions in intact tissues]

Spectra of fluorescence (SF) excited by the light with the wave length of 260 nm were measured with the aim of revealing the character of structural reconstructions in water-dificient plant cells. Hypocotyls of Cucumis sativus L. seedlings during soil draught served as the objects of study. With an increase of water deficiency the SF maximum is shifted to 5-8 nm to the long wave region. In wilted plant tissues free triptophane was accumulated whose SF maximum was shifted to the long wave region as compared to that of triptophane bound in proteins. The data obtained point to a limited usage of UV-fluorescence in detecting structural transitions of proteins in intact cells and tissues. In cases when the content of free triptophane is changed it is difficult to make certain conclusions about the character of conformational changes of protein macromolecules.