Proteins, nucleic acids and genetic codes.

Abstract

On the basis of the previous article (Morchio and Traverso [1999]), we discuss the possible interactions between the first proteic fragments developed in the hydrophobic layer made of hydrocarbons, which would have covered the surface of the primitive seas, and the nitrogenous bases, particularly the pyrimidinic ones, which would have found in such hydrophobic layer favourable conditions to their prebiotic synthesis. These interactions would have presumably brought, on the basis of the physicochemical laws, at the moment the only ones at work, to the linkage of various bases and so to the construction of the first nucleic acid chains (most likely RNA). Interestingly enough this result would have been obtained by inserting two more bases between those hydrogen bound to the amino acids and this might have been the ground for the future "triplets". These interactions might have been particularly significant because of two important consequences: the birth of a rough genetic code and the starting of interactions of the co-operative type between bases and amino acids that would have made the growth of both proteic and nucleic acid fragments easier and faster. We conclude that the development of the genetic code was neither a "frozen accident" nor an occurrence directed by any information flow.