title: A 3' to 5' exonuclease activity is associated with phage 029 DNA polymerase.
abstract: Bacteriophage 029 produces its own DNA polymerase which is encoded by gene 2 [Watabe, K. and Ito, J. (1983) Nucleic Acid Res. 11, 8333]. This 029 DNA polymerase has been purified by phospho-cellulose, DEAE-cellulose, double-stranded DNA cellulose chromatography and glycerol gradient centrifugation. An exonuclease activity associated with the DNA polymerase was found through all the steps of the purification. This nuclease preferably degrades single-stranded DNA from the 3' to the 5' terminus direction, suggesting that the enzyme plays a role for proofreading during DNA replication. While DNA polymerase activity isolated from cells infected with temperature sensitive mutant of gene 2 is thermolabile, the nuclease activity is not significantly reduced at the restrictive temperature.
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D001435:Bacteriophages / Q000201:enzymology*; D004259:DNA-Directed DNA Polymerase / Q000302:isolation & purification / Q000378:metabolism*; D005092:Exonucleases / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D009154:Mutation
chemical_list: D004259:DNA-Directed DNA Polymerase; D005092:Exonucleases