Une étape de l'évolution chimique: la formation de polypeptides et de polynucléotides dans des conditions prébiotiques

5. Internationales Makromolekulares Symposium

Abstract

Owing to a suitable enzymatic equipment the living cell synthesizes macromolecular chains (proteins, nucleic acids, polysaccharides) which can be considered as condensation products of the corresponding difunctionnal monomers (amino acids, nucleotides, sugars). 

If one looks at the different steps of the chemical evolution which has led to living cells, one has logically to look to the possibilities of building these chains without the enzymatic material and in aqueous solution. 

We will only consider here the synthesis of polypeptides and polynucleotides and examine the results obtained in the following way :

1. polycondensation of monomers (amino acids or nucleotides) dispersed in an homogeneous aqueous solution in presence of a dehydrating agent (carbodiimide, dicyanamide, etc.). Some simple polycondensation in organic mechanism will be evoqued,
2. the same reaction with additionnai presence of a preformed long chain; 
3. in the presence of a macroscopic heterogeneity either organic (coacervates, proteinoids, ... ) or mineral (clays). 

In conclusion, special attention is devoted to the possibility of nucleotides polycondensation catalyzed by synthetic polypeptides.