Polycytidylate and poly(7-deazaguanylate): a pair of complementary templates.
We have studied the template-directed oligomerization on polycytidylic acid of the 5'-phosphoro(2-methyl)imidazolides of a number of analogues of guanosine. None of the analogues reacted as efficiently as the original guanosine compound, and only the 7-deazaguanosine analogue gives a detectable yield of oligomers. Similar results are described for a reaction involving the intramolecular template-directed elongation of a short oligocytidylate primer. Oligocytidylates containing five or more cytidylate residues are extended on the single-stranded regions of poly(G). In the present study we show that these oligocytidylates are extended efficiently by reaction with cytidine-5'-phosphoro(2-methyl)imidazolide on a poly(7-deazaguanylic acid) template. The products are considerably longer than those obtained using a polyguanylic acid template. We believe that the formation of a tetrahelix inhibits the latter reaction, while poly(7-deazaguanylate) does not aggregate and, therefore, acts as a more efficient template. This work identifies for the first time a pair of homopolymers each of which facilitates the template-directed elongation of the other.
Rembold
H
H
BYK-Gulden-Lomberg, Department FC1, Konstanz, Germany.
Robins
R K
RK
Seela
F
F
Orgel
L E
LE
D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry; D006157:Guanosine Monophosphate / Q000031:analogs & derivatives; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D011066:Poly C / Q000737:chemistry*; D011068:Poly G / Q000737:chemistry*
D017931:DNA Primers; D009838:Oligodeoxyribonucleotides; D011068:Poly G; D011066:Poly C; D006147:Guanine; C036896:guanosine 5'-phospho-2-methylimidazolide; D006157:Guanosine Monophosphate; C066856:7-deazaguanine