title: Self-condensation of activated dinucleotides on polynucleotide templates with alternating sequences.
abstract: We have prepared substantial quantities of the alternating polymers poly(U-G) and poly(C-A) and have used them as templates for the self-condensation of ImpApC, ImpCpA, ImpGpU and ImpG. We find that the condensation of ImpGpU and ImpUpG on poly(C-A) is efficient, the condensation of ImpCpA on poly(U-G) is moderately efficient, while the condensation of ImpApC on poly(U-C) proceeds poorly. In many cases, the product is predominantly 3'-5'-linked. These reactions demonstrate unequivocally, for the first time, that template-directed reactions occur in double-helical structures. Furthermore, they describe for the first time a pair of reactions in which each of two complementary polymers facilitates the synthesis of the other. The prebiotic significance of these findings is discussed.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D007536:Isomerism; D009843:Oligoribonucleotides; D011061:Poly A / Q000494:pharmacology; D011066:Poly C / Q000494:pharmacology; D011068:Poly G / Q000494:pharmacology; D011072:Poly U / Q000494:pharmacology; D011131:Polyribonucleotides / Q000138:chemical synthesis*; D013698:Templates, Genetic
chemical_list: D009843:Oligoribonucleotides; D011131:Polyribonucleotides; D011061:Poly A; D011068:Poly G; C023795:poly(U-G); D011072:Poly U; C023794:poly(A-C); D011066:Poly C