title: A slow, tight-binding inhibitor of the zinc-dependent deacetylase LpxC of lipid A biosynthesis with antibiotic activity comparable to ciprofloxacin.
abstract: The zinc-dependent enzyme LpxC catalyzes the deacetylation of UDP-3-O-acyl-GlcNAc, the first committed step of lipid A biosynthesis. Lipid A is an essential component of the outer membranes of most Gram-negative bacteria, including Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa, making LpxC an attractive target for antibiotic design. The inhibition of LpxC by a novel N-aroyl-l-threonine hydroxamic acid (CHIR-090) from a recent patent application (International Patent WO 2004/062601 A2 to Chiron and the University of Washington) is reported here. CHIR-090 possesses remarkable antibiotic activity against both E. coli and P. aeruginosa, comparable to that of ciprofloxacin. The biological activity of CHIR-090 is explained by its inhibition of diverse LpxC orthologues at low nanomolar concentrations, including that of Aquifex aeolicus, for which structural information is available. The inhibition of A. aeolicus LpxC by CHIR-090 occurs in two steps. The first step is rapid and reversible, with a K(i) of 1.0-1.7 nM, depending upon the method of assay. The second step involves the conversion of the EI complex with a half-life of about a minute to a tightly bound form. The second step is functionally irreversible but does not result in the covalent modification of the enzyme, as judged by electrospray ionization mass spectrometry. CHIR-090 is the first example of a slow, tight-binding inhibitor for LpxC and may be the prototype for a new generation of LpxC inhibitors with therapeutic applicability.
authors.affiliation: Department of Biochemistry, Duke University Medical Center, Post Office Box 3711, Durham, North Carolina 27710, USA.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: McClerren
authors.forename: Stephanie
authors.initials: S
authors.lastname: Endsley
authors.forename: Jason L
authors.initials: JL
authors.lastname: Bowman
authors.forename: Niels H
authors.initials: NH
authors.lastname: Andersen
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Guan
authors.forename: Johannes
authors.initials: J
authors.lastname: Rudolph
authors.forename: Christian R H
authors.initials: CR
authors.lastname: Raetz
mesh_terms: D000581:Amidohydrolases / Q000737:chemistry / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D006877:Hydroxamic Acids / Q000737:chemistry / Q000494:pharmacology*; D008050:Lipid A / Q000096:biosynthesis*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D013912:Threonine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D015032:Zinc / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; C525369:CHIR 090; D004791:Enzyme Inhibitors; D006877:Hydroxamic Acids; D008050:Lipid A; D013912:Threonine; D002939:Ciprofloxacin; D000581:Amidohydrolases; C097307:UDP-3-O-acyl-N-acetylglucosamine deacetylase; D015032:Zinc