This Article Full Text Full Text (PDF) Other Versions of this Article: AAC.00596-06v1 51/2/657    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Grossman, T. H. Articles by Mani, N. Search for Related Content PubMed PubMed Citation Articles by Grossman, T. H. Articles by Mani, N.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, February 2007, p. 657-666, Vol. 51, No. 2
0066-4804/07/$08.00+0     doi:10.1128/AAC.00596-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Dual Targeting of GyrB and ParE by a Novel Aminobenzimidazole Class of Antibacterial Compounds

Trudy H. Grossman, Douglas J. Bartels, Steve Mullin, Christian H. Gross, Jonathan D. Parsons, Yusheng Liao, Anne-Laure Grillot, Dean Stamos, Eric R. Olson, Paul S. Charifson, and Nagraj Mani^*

Vertex Pharmaceuticals Incorporated, 130 Waverly St., Cambridge, Massachusetts 02139

Received 16 May 2006/ Returned for modification 21 July 2006/ Accepted 7 November 2006

A structure-guided drug design approach was used to optimize a novel series of aminobenzimidazoles that inhibit the essential ATPase activities of bacterial DNA gyrase and topoisomerase IV and that show potent activities against a variety of bacterial pathogens. Two such compounds, VRT-125853 and VRT-752586, were characterized for their target specificities and preferences in bacteria. In metabolite incorporation assays, VRT-125853 inhibited both DNA and RNA synthesis but had little effect on protein synthesis. Both compounds inhibited the maintenance of negative supercoils in plasmid DNA in Escherichia coli at the MIC. Sequencing of DNA corresponding to the GyrB and ParE ATP-binding regions in VRT-125853- and VRT-752586-resistant mutants revealed that their primary target in Staphylococcus aureus and Haemophilus influenzae was GyrB, whereas in Streptococcus pneumoniae it was ParE. In Enterococcus faecalis, the primary target of VRT-125853 was ParE, whereas for VRT-752586 it was GyrB. DNA transformation experiments with H. influenzae and S. aureus proved that the mutations observed in gyrB resulted in decreased susceptibilities to both compounds. Novobiocin resistance-conferring mutations in S. aureus, H. influenzae, and S. pneumoniae were found in gyrB, and these mutants showed little or no cross-resistance to VRT-125853 or VRT-752586 and vice versa. Furthermore, gyrB and parE double mutations increased the MICs of VRT-125853 and VRT-752586 significantly, providing evidence of dual targeting. Spontaneous frequencies of resistance to VRT-752586 were below detectable levels (<5.2 x 10^–10) for wild-type E. faecalis but were significantly elevated for strains containing single and double target-based mutations, demonstrating that dual targeting confers low levels of resistance emergence and the maintenance of susceptibility in vitro.

Published ahead of print on 20 November 2006.

Present address: Novartis Pharmaceuticals, Cambridge, MA.

This article has been cited by other articles:

• Ostrov, D. A., Hernandez Prada, J. A., Corsino, P. E., Finton, K. A., Le, N., Rowe, T. C. (2007). Discovery of Novel DNA Gyrase Inhibitors by High-Throughput Virtual Screening. Antimicrob. Agents Chemother. 51: 3688-3698 [Abstract] [Full Text]