[Study of the binding of the S7 protein with 16S rRNA fragment 926-986/1219-1393 as a key step in the assembly of the small subunit of prokaryotic ribosomes].

Both structural and thermodynamic studies are necessary to understand the ribosome assembly. An initial step was made in studying the interaction between a 16S rRNA fragment and S7, a key protein in assembling the prokaryotic ribosome small subunit. The apparent dissociation constant was obtained for complexes of recombinant Escherichia coli and Thermus thermophilus S7 with a fragment of the 3' domain of the E. coli 16S rRNA. Both proteins showed a high rRNA-binding activity, which was not observed earlier. Since RNA and proteins are conformationally labile, their folding must be considered to correctly describe the RNA-protein interactions.