Conformational changes in 16S ribosomal RNA induced by 30S ribosomal subunit proteins from Escherichia coli.

Laser light scattering has been used to evaluate conformational differences between free 16S RNA and several specific protein-16S RNA complexes. Proteins that interact strongly with the 16S RNA early in subunit assembly stabilize the RNA chain against unfolding in 1 mM Mg2+ and actually promote the formation of a more compact teriary structure in 20 mM Mg2+. A vital function of these proteins may therfore consist in altering the configuration of the RNA so that further assembly reactions can take place.