Structure of the 16S and 23S Ribosomal RNAs

Abstract

INTRODUCTION
The important role of the rRNAs in establishing and maintaining the structure of ribosomes has been clearly revealed by extensive studies on the reconstitution of ribosomal particles (see Nomura and Held, this volume). The rRNAs appear to provide the framework to which the ribosomal proteins are attached during assembly. In the mature ribosome, they hold the proteins in a configuration which permits the particle to correctly carry out its functions in protein biosynthesis. The conformations of the RNA and protein molecules and the manner in which they are associated together result from a variety of interactions, both inter- and intramolecular. These interactions, which are cooperative, cause the RNA and protein components to assume specific secondary and tertiary structures and to become attached to each other in a precise way.

In view of the fundamental role of rRNAs, considerable efforts have been made in the last few years to determine their nucleotide sequences. Extensive information about the primary structures of these molecules is necessary in order to gain a more detailed understanding of their role in ribosome structure, function and assembly and might also provide a means of resolving several questions concerning the genetics and evolution of ribosomes. In particular, such knowledge should prove helpful in clarifying the following areas:Primary sequence data is expected to give some indication of the secondary structures of the rRNA molecules, both from consideration of the sequences themselves and from the relative susceptibilities of specific bonds within them to enzymatic digestion. In any...