The amino acid sequence required for 5' --> 3' exonuclease activity of Bacillus caldotenax DNA polymerase.
We studied the 5' --> 3' exonuclease activity of Bacillus caldotenax DNA polymerase by site-directed mutagenesis. Among seven mutants constructed, two mutant DNA polymerases with an amino acid substitution of Gly184 --> Asp or Gly192 --> Asp were confirmed to be deficient in this exonuclease. The two positions corresponded to those of the Escherichia coli DNA polymerase I mutants defective in 5' --> 3' exonuclease, polA480ex and polA214. These results provide experimental support for the proposed amino acid sequence essential for the 5' --> 3' exonuclease activity associated with eubacterial polymerase I-like DNA polymerases (family A), including E.coli and Thermus aquaticus.
Ishino
Y
Y
Biotechnology Research Laboratories, Takara Shuzo Co., Ltd., Shiga, Japan.
Takahashi-Fujii
A
A
Uemori
T
T
Imamura
M
M
Kato
I
I
Doi
H
H
D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D004256:DNA Polymerase I / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011994:Recombinant Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship
D011994:Recombinant Proteins; D004256:DNA Polymerase I; D005090:Exodeoxyribonucleases; D043211:Exodeoxyribonuclease V