title: 3,5-dioxopyrazolidines, novel inhibitors of UDP-N- acetylenolpyruvylglucosamine reductase (MurB) with activity against gram-positive bacteria.
abstract: A series of 3,5-dioxopyrazolidines was identified as novel inhibitors of UDP-N-acetylenolpyruvylglucosamine reductase (MurB). Compounds 1 to 3, which are 1,2-bis(4-chlorophenyl)-3,5-dioxopyrazolidine-4-carboxamides, inhibited Escherichia coli MurB, Staphyloccocus aureus MurB, and E. coli MurA with 50% inhibitory concentrations (IC50s) in the range of 4.1 to 6.8 microM, 4.3 to 10.3 microM, and 6.8 to 29.4 microM, respectively. Compound 4, a C-4-unsubstituted 1,2-bis(3,4-dichlorophenyl)-3,5-dioxopyrazolidine, showed moderate inhibitory activity against E. coli MurB, S. aureus MurB, and E. coli MurC (IC50s, 24.5 to 35 microM). A fluorescence-binding assay indicated tight binding of compound 3 with E. coli MurB, giving a dissociation constant of 260 nM. Structural characterization of E. coli MurB was undertaken, and the crystal structure of a complex with compound 4 was obtained at 2.4 A resolution. The crystal structure indicated the binding of a compound at the active site of MurB and specific interactions with active-site residues and the bound flavin adenine dinucleotide cofactor. Peptidoglycan biosynthesis studies using a strain of Staphylococcus epidermidis revealed reduced peptidoglycan biosynthesis upon incubation with 3,5-dioxopyrazolidines, with IC50s of 0.39 to 11.1 microM. Antibacterial activity was observed for compounds 1 to 3 (MICs, 0.25 to 16 microg/ml) and 4 (MICs, 4 to 8 microg/ml) against gram-positive bacteria including methicillin-resistant S. aureus, vancomycin-resistant Enterococcus faecalis, and penicillin-resistant Streptococcus pneumoniae.
authors.affiliation: Wyeth Research, 401 North Middletown Rd., Pearl River, NY 10965, USA.
authors.forename: Youjun
authors.initials: Y
authors.lastname: Yang
authors.forename: Anatoly
authors.initials: A
authors.lastname: Severin
authors.forename: Rajiv
authors.initials: R
authors.lastname: Chopra
authors.forename: Girija
authors.initials: G
authors.lastname: Krishnamurthy
authors.forename: Guy
authors.initials: G
authors.lastname: Singh
authors.forename: William
authors.initials: W
authors.lastname: Hu
authors.forename: David
authors.initials: D
authors.lastname: Keeney
authors.forename: Kristine
authors.initials: K
authors.lastname: Svenson
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Petersen
authors.forename: Pornpen
authors.initials: P
authors.lastname: Labthavikul
authors.forename: David M
authors.initials: DM
authors.lastname: Shlaes
authors.forename: Beth A
authors.initials: BA
authors.lastname: Rasmussen
authors.forename: Amedeo A
authors.initials: AA
authors.lastname: Failli
authors.forename: Jay S
authors.initials: JS
authors.lastname: Shumsky
authors.forename: Kristina M K
authors.initials: KM
authors.lastname: Kutterer
authors.forename: Adam
authors.initials: A
authors.lastname: Gilbert
authors.forename: Tarek S
authors.initials: TS
authors.lastname: Mansour
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002237:Carbohydrate Dehydrogenases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D003461:Crystallography; D005453:Fluorescence; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010457:Peptidoglycan / Q000096:biosynthesis; D011485:Protein Binding; D011720:Pyrazoles / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010457:Peptidoglycan; D011720:Pyrazoles; D002237:Carbohydrate Dehydrogenases; C023215:UDP-N-acetylmuramate dehydrogenase