Replication of poly dA and poly rA by a drosophila DNA polymerase.
The activity of a 7.3S-8.3S Drosophila DNA polymerase was characterized in detail using poly dA.p(dT)[unk] and poly rA.p(dT)[unk]. With poly dA.p(dT)[unk], Mg(2+) ion was the preferred divalent cation, and enzyme activity was inhibited by K(+) ion and by spermidine. With poly rA.p(dT)[unk], Mn(2+) ion was the preferred divalent cation and enzyme activity was stimulated by K(+) ion and by spermidine. The dependence of enzyme activity on the concentration of primer-template and on the ratio of primer to template was the same in both reactions. The two enzyme activities were identically inhibited by N-ethylmaleimide. Poly dA was replicated extensively and poly rA was replicated partially. The activation energy for poly dA replication was twice that for poly rA replication. Enzyme activity with poly dA.p(dT)[unk] was more stable to thermal inactivation than was enzyme activity with poly rA.p(dT)[unk]. These studies suggest that the same enzyme responds to both the deoxy- and the ribohomopolymer template but that the mechanisms of replication may be different.
D002413:Cations, Divalent / Q000494:pharmacology; D002414:Cations, Monovalent / Q000494:pharmacology; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000201:enzymology*; D019384:Nucleic Acid Synthesis Inhibitors; D011061:Poly A / Q000378:metabolism; D011071:Poly T / Q000096:biosynthesis; D011089:Polydeoxyribonucleotides / Q000378:metabolism; D013095:Spermidine / Q000494:pharmacology; D013379:Substrate Specificity; D013696:Temperature; D013698:Templates, Genetic
D002413:Cations, Divalent; D002414:Cations, Monovalent; D019384:Nucleic Acid Synthesis Inhibitors; D011089:Polydeoxyribonucleotides; D011061:Poly A; D011071:Poly T; D004259:DNA-Directed DNA Polymerase; D013095:Spermidine