USE OF FLUORESCENCE PROBES 1-ANILINE-8-NAPHTHALENE SULFONATE AND PYRENE FOR STUDYING THE LOCALIZATION OF PROTEINS IN INNER MEMBRANES FROM WHEAT ETIOPLASTS

The fluorescence probes 1-aniline-8-naphthalene sulfonate (ANS) and py rene were applied for characterisation of the light-induced changes in etioplast inner membranes (EPIMs) from 7 d-old dark-grown wheat seedl ings (Triticum aestivum L. cv. Pobeda). The major aim was to obtain in formation about the localisation of membrane proteins in the EPIMs, us ing probes situated in different regions of the membranes. The quenchi ng of tryptophan fluorescence showed that the main parts of proteins w ere accessible to the pyrene buried in the lipid bilayer which suggest s that most of the proteins also enter the lipid bilayer. The substant ial quenching of the tryptophan fluorescence by the surface-situated A NS demonstrated that a part of the tryptophan residues was probably lo calised close to the membrane surface. The registered changes after ir radiation could be explained by the presence of large aggregates of NA DPH-protochlorophyllide oxidoreductase (POR), protochlorophyllide (PCh lide) and NADPH in membranes that start to disconnect and redistribute along the prothylakoids.