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Updated: Jul 20, 2026

Atomic Force Microscopy Investigations of DNA Lesion Recognition in Nucleotide Excision Repair
Published on: May 24, 2017
The amino acid sequence required for 5' --> 3' exonuclease activity of Bacillus caldotenax DNA polymerase
Y Ishino1, A Takahashi-Fujii, T Uemori
1Biotechnology Research Laboratories, Takara Shuzo Co., Ltd., Shiga, Japan.
Abstract:
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.
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