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Conserved motifs II to VI of DNA helicase II from Escherichia coli are all required for biological activity.

Publication ,  Journal Article
Zhang, G; Deng, E; Baugh, LR; Hamilton, CM; Maples, VF; Kushner, SR
Published in: Journal of bacteriology
December 1997

There are seven conserved motifs (IA, IB, and II to VI) in DNA helicase II of Escherichia coli that have high homology among a large family of proteins involved in DNA metabolism. To address the functional importance of motifs II to VI, we employed site-directed mutagenesis to replace the charged amino acid residues in each motif with alanines. Cells carrying these mutant alleles exhibited higher UV and methyl methanesulfonate sensitivity, increased rates of spontaneous mutagenesis, and elevated levels of homologous recombination, indicating defects in both the excision repair and mismatch repair pathways. In addition, we also changed the highly conserved tyrosine(600) in motif VI to phenylalanine (uvrD309, Y600F). This mutant displayed a moderate increase in UV sensitivity but a decrease in spontaneous mutation rate, suggesting that DNA helicase II may have different functions in the two DNA repair pathways. Furthermore, a mutation in domain IV (uvrD307, R284A) significantly reduced the viability of some E. coli K-12 strains at 30 degrees C but not at 37 degrees C. The implications of these observations are discussed.

Duke Scholars

Published In

Journal of bacteriology

DOI

EISSN

1098-5530

ISSN

0021-9193

Publication Date

December 1997

Volume

179

Issue

23

Start / End Page

7544 / 7550

Related Subject Headings

  • Ultraviolet Rays
  • Recombination, Genetic
  • Mutagenesis, Site-Directed
  • Molecular Sequence Data
  • Microbiology
  • Methyl Methanesulfonate
  • Escherichia coli
  • Dose-Response Relationship, Radiation
  • Dose-Response Relationship, Drug
  • DNA Repair
 

Citation

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Zhang, G., Deng, E., Baugh, L. R., Hamilton, C. M., Maples, V. F., & Kushner, S. R. (1997). Conserved motifs II to VI of DNA helicase II from Escherichia coli are all required for biological activity. Journal of Bacteriology, 179(23), 7544–7550. https://doi.org/10.1128/jb.179.23.7544-7550.1997
Zhang, G., E. Deng, L. R. Baugh, C. M. Hamilton, V. F. Maples, and S. R. Kushner. “Conserved motifs II to VI of DNA helicase II from Escherichia coli are all required for biological activity.Journal of Bacteriology 179, no. 23 (December 1997): 7544–50. https://doi.org/10.1128/jb.179.23.7544-7550.1997.
Zhang G, Deng E, Baugh LR, Hamilton CM, Maples VF, Kushner SR. Conserved motifs II to VI of DNA helicase II from Escherichia coli are all required for biological activity. Journal of bacteriology. 1997 Dec;179(23):7544–50.
Zhang, G., et al. “Conserved motifs II to VI of DNA helicase II from Escherichia coli are all required for biological activity.Journal of Bacteriology, vol. 179, no. 23, Dec. 1997, pp. 7544–50. Epmc, doi:10.1128/jb.179.23.7544-7550.1997.
Zhang G, Deng E, Baugh LR, Hamilton CM, Maples VF, Kushner SR. Conserved motifs II to VI of DNA helicase II from Escherichia coli are all required for biological activity. Journal of bacteriology. 1997 Dec;179(23):7544–7550.

Published In

Journal of bacteriology

DOI

EISSN

1098-5530

ISSN

0021-9193

Publication Date

December 1997

Volume

179

Issue

23

Start / End Page

7544 / 7550

Related Subject Headings

  • Ultraviolet Rays
  • Recombination, Genetic
  • Mutagenesis, Site-Directed
  • Molecular Sequence Data
  • Microbiology
  • Methyl Methanesulfonate
  • Escherichia coli
  • Dose-Response Relationship, Radiation
  • Dose-Response Relationship, Drug
  • DNA Repair