PMID: 17696333

Authors:

Bennett BC, Xu H, Simmerman RF, Lee RE, Dealwis CG

Title:

Crystal structure of the anthrax drug target, Bacillus anthracis dihydrofolate reductase.

Journal:

J Med Chem. 2007 Sep 6;50(18):4374-81. Epub 2007 Aug 14.

Abstract:

Spores of Bacillus anthracis are the infectious agent of anthrax. Current antibiotic treatments are limited due to resistance and patient age restrictions; thus, additional targets for therapeutic intervention are needed. One possible candidate is dihydrofolate reductase (DHFR), a biosynthetic enzyme necessary for anthrax pathogenicity. We determined the crystal structure of DHFR from B. anthracis (baDHFR) in complex with methotrexate (MTX; 1) at 2.4 Angstrom resolution. The structure reveals the crucial interactions required for MTX binding and a putative molecular basis for how baDHFR has natural resistance to trimethoprim (TMP; 2). The structure also allows insights for designing selective baDHFR inhibitors that will have weak affinities for the human enzyme. Additionally, we have found that 5-nitro-6-methylamino-isocytosine (MANIC; 3), which inhibits another B. anthracis folate synthesis enzyme, dihydropteroate synthase (DHPS), can also inhibit baDHFR. This provides a starting point for designing multi-target inhibitors that are less likely to induce drug resistance.