Open AccessAnthrax lethal factor inhibition
Author(s) -
Wesley L. Shoop,
Yusheng Xiong,
Judyann Wiltsie,
Andrea Woods,
Jian Guo,
James V. Pivnichny,
T. Felcetto,
B. F. Michael,
Alka Bansal,
Richard Cummings,
Barry R. Cunningham,
Arthur M. Friedlander,
Cameron M. Douglas,
Sangita Patel,
Douglas Wisniewski,
Giovanna Scapin,
Scott P. Salowe,
Dennis M. Zaller,
Kevin T. Chapman,
Edward M. Scolnick,
Dennis M. Schmatz,
Ken Bartizal,
Malcolm MacCoss,
Jeffrey D. Hermes
Publication year - 2005
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0502159102
Subject(s) - bacillus anthracis , anthrax toxin , microbiology and biotechnology , virulence factor , biology , lethal dose , virulence , toxin , recombinant dna , biochemistry , bacteria , toxicology , genetics , gene , fusion protein
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) approximately 50% 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.