Nonenzymatic Oligomerization Reactions on Templates Containing Inosinic Acid or Diaminopurine Nucleotide Residues

摘要

The template-directed oligomerization of nucleoside-5'phosphoro-2-methyl imidazolides on standard oligonucleotide templates has been studied extensively.Here,we describe experiments with templates in which inosinic acid(I)is substituted for guanylic acid,or 2,6-diaminopurine nucleotide(D) for adenylic acid.We find that the substitution of I for Gin a template is strongly inhibitory and prevents any incorporation of C into internal positions in the oligomeric products of the reaction.The substitution of D for A,on the contrary,leads to increased incorporation of U into the products.We found no evidence for the template-directed facilitation of oligomerization of A or I through A-I base pairing.The significance of these results for prebiotic chemistry is discussed.