Novel Inhibitor of E. coli DNA Adenine Methyltransferase (Ecodam)
EcoDam is an adenine-N6 DNA methyltransferase
that methylates the GATC sites in the Escherichia coli genome.
DNA-adenine methylation is not present in higher eukaryotes
including humans. These observations raise the possibility that dam
inhibitors may be used as anti-microbial agents. Polyphosphate
(Poly(P)) is an important metabolite and signaling molecule in
prokaryotes and eukaryotes. Here, by using gel retardation
experiments to investigate the competition of DNA binding by
EcoDam in the presence of polyphosphate, we found that Poly (P)
strongly interferes with DNA binding by EcoDam, while same
concentration of monophosphate does not. In addition, we
demonstrated that Poly (P) binding inhibits the activity of EcoDam
and our results suggest that Poly (P) led to strong inhibition of the
EcoDam catalytic activity, while monophosphate had only moderate
Cassell, G. H. and Mekalanos, J. (2001) Development of antimicrobial
agents in the Era of new reemerging infectious diseases and increasing
antibiotic resistance. J. Am. Med. Assoc. 285, 601-605.
Jeltsch, A. (2002) Beyond Watson and Crick: DNA methylation and
molecular enzymology of DNA methyltransferases. ChemBioChem. 3,
Mahan, M. J. and Low, D. A. (2001) DNA methylation regulates
bacterial gene expression and virulence. ASM News. 67, 356-361.
Mahan, M. J., Heithoff, D. M., Sinsheimer, R. L. and Low, D. A. (2000)
Assessment of bacterial pathogenesis by analysis of gene expression in
the host. Ann. Rev. Genet. 34, 139-164.
Nakao, M. (2001) Epigenetics: interaction of DNA methylation and
chromatin. Gene. 278, 25-31.
Robertson, K. D. and Wolffe, A. P. (2000) DNA methylation in health
and disease. Nat. Rev. Genet. 1, 11-19.
Taylor, V. L., Titball, R. W. and Oyston, P. C. F. (2005) Oral
immunization with a dam mutant of Yersinia pseudotuberculosis
protects against plague. Microbiology. 151, 1919-1926.
Waston, M. E., Jarisch, J. and Smith, A. L. (2004) Inactivation of
deoxyadenosine methyltransferase (dam) attenuates Haemophilus
influenzae virulence. Mol. Microbiol. 55, 651-654.
 Chen, L., Paulsen, D. B., Scruggs, D. W., Banes, M. M., Reeks, B. Y.
and Lawrence, M. L. (2003) Alteration of DNA adenine methylase
(Dam) activity in Pasteurella multocida causes increased spontaneous
mutation frequency and attenuation in mice. Microbiology. 149, 2283-
 Julio, S. M., Heithoff, D. M., Sinsheimer, R. L., Low, D. A. and Mahan,
M. J. (2002) DNA adenine methylase overproduction in Yersinia
pseudotuberculosis alters YopE expression and secretion and host
immune responses to infection. Infect. Immun. 70, 1006-1009.
 Honma, Y., Fernandez, R. E. and Maurelli, A. T. (2004) A DNA adenine
methylase mutant of Shigella flexneri shows no significant attenuation of
virulence. Microbiology. 150, 1073-1078.
 Horton, J. R., Liebert, K., Bekes, M., Jeltsch, A. and Cheng, X. (2006)
Structure and substrate recognition of the Escherichia coli DNA
Adenine methyltransferase. J. Mol. Biol. 358, 559-570.
 Pace, C. N., Vajdos, F., Fee, L., Grimsley, G. and Gray, T. (1995) How
to measure and predict the molar absorption coefficient of a protein.
Protein Sci. 4 (11), 2411-2423.
 Roth, M. & Jeltsch, A. (2000) Biotin-Avidin microtiter plate assay for
quantitative analysis of DNA methylation by DNA methyltransferases.
Biol. Chem. 381, 269-272.
 Elsawy, H., Podobinschi, S., Chahar, S. and Jeltsch, A. (2009)
Transition from EcoDam to T4Dam DNA recognition mechanism
without loss of activity and specificity, ChemBioChem. 10, 2488-2493.
Zweiger, G., Marczynski, G. and Shapiro, L. (1994) A Caulobacter
DNA methyltransferase that functions only in the predivisional cell. J.
Mol. Biol. 235, 472-485.