General Physical Properties of Ribosomes

Abstract

INTRODUCTION
This chapter is concerned with the morphology and structure of ribosomes, as revealed by physicochemical techniques. To attempt a comprehensive review of all reported measurements would be a formidable and unrewarding task. Rather, we feel that what is needed at this point is a critical review, which selects those observations that appear to be best documented. We shall attempt to correlate and interrelate these observations in such a manner as to provide a comprehensive picture of what we now know, or think we know, about ribosome structure.

In doing this, we are almost forced into proposing tentative models. These models may be useful, not because our knowledge of ribosome structure is complete, but because it is incomplete. Models provide a means of summarizing existing data in a way that provokes further questions and of focusing on the areas of our ignorance. Finally, they allow concentration on the interrelation between structure and function. We believe that our knowledge of ribosome structure is now at the stage where such questions can be seriously considered.

STRUCTURE OF E. COLI RIBOSOMES
Scope and Difficulties
In this section, we shall limit discussion to the 70S ribosomes of E. coli and the 50S and 30S subunits thereof. While we recognize that the ribosomes of other prokaryotes and eukaryotes may be of equal or greater interest to many, it is only with the E. coli particles that enough precise information has been gathered to present a coherent picture of physical properties. We presume, with some evidence...