Anthrax lethal factor inhibition

Abstract

The primary virulence factor of Bacillus anthracis is a secreted zinc-dependent metalloprotease toxin known as lethal factor (LF) that is lethal to the host through disruption of signaling pathways, cell destruction, and circulatory shock. Inhibition of this proteolytic-based LF toxemia could be expected to provide therapeutic value in combination with an antibiotic during and immediately after an active anthrax infection. Herein is shown the crystal structure of an intimate complex between a hydroxamate, (2R)-2-[(4-fluoro-3-methylphenyl)sulfonylamino]-N-hydroxy-2-(tetrahydro-2H-pyran-4-yl)acetamide, and LF at the LF-active site. Most importantly, this molecular interaction between the hydroxamate and the LF active site resulted in (i) inhibited LF protease activity in an enzyme assay and protected macrophages against recombinant LF and protective antigen in a cell-based assay, (ii) 100% protection in a lethal mouse toxemia model against recombinant LF and protective antigen, (iii) Ϸ50% survival advantage to mice given a lethal challenge of B. anthracis Sterne vegetative cells and to rabbits given a lethal challenge of B. anthracis Ames spores and doubled the mean time to death in those that died in both species, and (iv) 100% protection against B. anthracis spore challenge when used in combination therapy with ciprofloxacin in a rabbit ''point of no return'' model for which ciprofloxacin alone provided 50% protection. These results indicate that a small molecule, hydroxamate LF inhibitor, as revealed herein, can ameliorate the toxemia characteristic of an active B. anthracis infection and could be a vital adjunct to our ability to combat anthrax. Bacillus anthracis ͉ hydroxamate

Retrocyclins Kill Bacilli and Germinating Spores of Bacillus anthracis and Inactivate Anthrax Lethal Toxin

“…The results shown in Fig. 5 (b and c) (40). The docking results are summarized in Table 4 with the final docked energy listed for the best docked ligands.…”

“…In the present work all protein and ligand hydrogen atoms were explicitly modeled, with polar and nonpolar atoms being assigned Lennard-Jones 12-10 and 12-6 parameters, respectively. They were added to the native and ligand complexed forms of anthrax lethal factor (Protein Data Bank designations 1J7N (38), 1PWW (39), and 1YQY) (40) and the ligand (L2) of 1PWW using the WHAT IF web interface (41).…”

Anthrax toxin-induced rupture of artificial lipid bilayer membranes

“…If the translocation models are to hold, they must measure up to experiments with full-length LF and EF using conditions that accurately mimic the acidification of the endosome. Moreover, full-length LF and EF are three times larger than LF N , and have catalytic domains 88 that must remain functional after putative transport.…”

Sepsis and Pathophysiology of Anthrax in a Nonhuman Primate Model

“…These observations are further compounded by the current paradigm, based on toxic murine models, which describes anthrax pathogenesis as being governed by exotoxin bioactivities and host inflammatory or coagulopathic responses as playing little role. [25][26][27] These disparities gain importance when extrapolating experimental data to patients because vaccine development and clinical management decisions are based on an understanding of disease pathogenesis.…”