Abstract
T-5-induced DNA polymerase has been shown to possess a 3' leads to 5'-exonucleolytic activity. The exonuclease acts on both native and denatured DNA, but the apparent rate of degradation of denatured DNA is about five times faster than that for native DNA. The enzyme appears to act only on 3'-OH ends and produces mainly 5'-dNMP's. Like polymerase activity, exonuclease activity shows a pH optimum around 8.6. Mg2+, dithiothreitol, and N-ethylmaleimide had identical effects on both the activities. Nicked DNA was almost totally protected from exonuclease action under synthetic conditions, i.e., in the presence of 4dNTP's. Denatured DNA was partly degraded in the early phase of incubation with 4dNTP's, presumably due to unhybridized tails at the 3'-OH primer ends. However, the exonuclease activity was operative in both cases under synthetic conditions, as evidenced by template-dependent conversion of [3H]dTTP to [3H]dTMP.
Publisher
American Society for Microbiology
Subject
Virology,Insect Science,Immunology,Microbiology
Reference26 articles.
1. Enzymatic synthesis of deoxyribonucleic acid. IX. The polymerase formed after T2 bacteriophage infection ofE. coli: a new enzyme;Aposhian H. V.;J. Biol. Chem.,1962
2. Enzymatic synthesis of deoxyribonucleic acid. XXXVI. A proofreading function for the 3'-.5' exonuclease activity in deoxyribonucleic acid polymerases;Brutlag D.;J. Biol. Chem.,1972
3. Enzymic synthesis of DNA. XXXIII. Hydrolysis of a 5'-triphosphate-terminated polynucleotide in the active center of DNA polymerase;Cozzarelli N. R.;J. Mol. Biol.,1969
4. The structural gene for deoxyribonucleic acid polymerase in bacteriophages T4 and T5;DeWaard A.;Proc. Natl. Acad. Sci. U.S.A.,1965
5. The initial step of in vitro synthesis of deoxyribonucleic acid by the T4 deoxyribonucleic acid polymerase;Englund P. T.;J. Biol. Chem.,1971
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