Structure and Function of Eukaryotic Ribosomes

Abstract

INTRODUCTION
The unraveling of the structure and insight into the details of the function of prokaryotic ribosomes is derived from three technological advances, each an extraordinary achievement: the isolation, purification and characterization of the 55 proteins of E. coli ribosomes (see Wittmann, this volume); the reconstitution of active ribosomal subunits from their molecular components, i.e., from RNA and protein (see Nomura and Held, this volume); and finally the application of immunochemical techniques to their analysis (see Stöffler, this volume). The critical achievement was the separation of the ribosomal proteins; it made everything else (including re-constitution and the immunochemistry) possible.

The structure of ribosomal 5S RNA was determined by Sanger and his associates (Brownlee, Sanger and Barrell 1968) some time ago; the sequence of nucleotides in 16S RNA has been all but completed (Fellner et al. 1972) and that of 23S RNA is well under way (see Fellner, this volume). Thus there is a great likelihood that the primary structure of all the components of prokaryotic ribosomes will soon be known. The situation with respect to eukaryotic ribosomes is not nearly so far advanced. The individual proteins of eukaryotic ribosomes have not been isolated (in significant amounts), nor have they been purified or characterized, and that is a major impediment to further progress in analysis of the structure and function of the particles. There is no practical means of reconstituting functional eukaryotic ribosomes from their components, and only very limited use has been made of antibodies to study animal ribosomes.

All...