THE DYNAMIC CONFORMATION OF PLANT CYTOPLASMIC 5S RIBOSOMAL-RNAS

Recently we have proposed a new three-dimensional model of plant 5S rR NAs structure. To verify this proposal we present here new data on RNa se T-1 digestion and hydroxyl radical hydrolysis of lupin and wheat ge rm 5S rRNAs at various buffer and temperature conditions. Interestingl y, the guanosine residues 85-87 in the loop D of these RNAs, are resis tant to RNase T-1 at native but not at denaturating conditions. On the other hand the reaction of 5S rRNA with the hydroxyl radicals showed different reactivity of many nucleotides in various parts of the molec ule and suggest conformational changes, which occur mostly in the loop s. The experimental data clearly support involvement of the nucleotide s occupying conserved positions in the loops in the tertiary interacti ons in plant 5S rRNA structure.