Transfer of the nucleic acid information into protein structure, and some aspects of the structure and function of the translating organelle

Abstract

The metabolism of a cell is characterized by two features: 1. The network of chemical reactions is defined by the pattern of enzymes. 2. In vivo the biochemical reactions run far from their thermodynamical equilibrium, which is made possible by the prevalence of the ATP over its hydrolytic products. If we compare the metabolism with a channel network, then the enzyme pattern defines the architecture, and the ATP to ADP ratio the flow rate of the system. Practically all the enzymes are proteins. Proteins have additional regulatory functions and important structural tasks, they comprise 50% of the cell’s dry mass. For these reasons, in molecular biology heredity means first and above all the heredity of structural information on both proteins and the protein-synthesizing machinery. The fundamental molecular processes of heredity, i. e. the preservation and the realization of the genetic information, are based on the simple rule of complementary base-pairing, resulting in the translation of the genetic information into the defined amino acid sequence of a protein. The amino acid sequence in turn determines the routes of folding and thus the spatial structure of a protein (“folding code”).

The ribosome is the organelle of translation. Three aspects are surveyed: 1. Principles of assembly of the large subunit from procaryotic ribosomes (Escherichia coli). 2. Neutron scattering as a method for the analysis of the internal topography of ribosomes. 3. Description of ribosomal functions in the frame of a model containing three tRNA binding sites.

Lecture presented during the 32nd Annual Meeting of the Kolloid-Gesellschaft, Berlin October 2–4, 1985.