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.
Subject(s)
Anti-Bacterial Agents/pharmacology , Carbohydrate Dehydrogenases/antagonists & inhibitors , Gram-Positive Bacteria/drug effects , Pyrazoles/pharmacology , Carbohydrate Dehydrogenases/chemistry , Carbohydrate Dehydrogenases/metabolism , Crystallography , Fluorescence , Microbial Sensitivity Tests , Peptidoglycan/biosynthesis , Protein BindingABSTRACT
Pulvinones were synthesized (>180) in arrays and evaluated as inhibitors of early stage cell wall biosynthesis enzymes MurA-MurD. Several pulvinones inhibited Mur enzymes with IC(50)'s in the 1-10 microg/mL range and demonstrated antibacterial activity against Gram-positive bacteria including methicillin-resistant Staphyloccus aureus, vancomycin-resistant Enterococcus faecalis, and penicillin-resistant Streptococcus pneumoniae.
Subject(s)
Carboxylic Acids/chemical synthesis , Lactones/chemical synthesis , Streptococcus pneumoniae/metabolism , Anti-Bacterial Agents/pharmacology , Anti-Infective Agents/pharmacology , Cell Wall/drug effects , Cell Wall/metabolism , Drug Resistance, Bacterial , Enterococcus faecalis/metabolism , Inhibitory Concentration 50 , Methicillin/pharmacology , Microbial Sensitivity Tests , Models, Chemical , Penicillins/pharmacology , Staphylococcus aureus/metabolism , Vancomycin/pharmacologyABSTRACT
Over 195 4-alkyl and 4,4-dialkyl 1,2-bis(4-chlorophenyl)pyrazolidine-3,5-dione derivatives were synthesized, utilizing microwave accelerated synthesis, for evaluation as new inhibitors of bacterial cell wall biosynthesis. Many of them demonstrated good activity against MurB in vitro and low MIC values against gram-positive bacteria, particularly penicillin-resistant Streptococcus pneumoniae (PRSP). Derivative 7l demonstrated antibacterial activity against both gram-positive and gram-negative bacteria. Derivatives 7f and 10a also demonstrated potent nanomolar Kd values in their binding to MurB.
Subject(s)
Cell Wall/drug effects , Gram-Positive Bacteria/drug effects , Pyrazoles/pharmacology , Cell Wall/metabolism , Gram-Positive Bacteria/metabolism , Molecular StructureABSTRACT
Over 50 phenyl thiazolyl urea and carbamate derivatives were synthesized for evaluation as new inhibitors of bacterial cell-wall biosynthesis. Many of them demonstrated good activity against MurA and MurB and gram-positive bacteria including MRSA, VRE and PRSP. 3,4-Difluorophenyl 5-cyanothiazolylurea (3p) with clog P of 2.64 demonstrated antibacterial activity against both gram-positive and gram-negative bacteria.
Subject(s)
Anti-Bacterial Agents/pharmacology , Carbamates/chemistry , Carbamates/pharmacology , Peptidoglycan/biosynthesis , Phenylthiazolylthiourea/analogs & derivatives , Phenylthiazolylthiourea/pharmacology , Cell Wall/drug effects , Cell Wall/enzymology , Enterococcus faecalis/drug effects , Enterococcus faecalis/enzymology , Escherichia coli/drug effects , Escherichia coli/enzymology , Microbial Sensitivity Tests , Staphylococcus/drug effects , Staphylococcus/enzymologyABSTRACT
A series of Muraymycin analogues was synthesized. These analogues showed excellent antimicrobial activity against gram-positive organisms. These analogues also showed excellent inhibitory activity against the target peptidoglycan biosynthesis enzyme MraY, the cell membrane associated transglycosylase responsible for the formation of Lipid II.
Subject(s)
Peptidoglycan/analogs & derivatives , Peptidoglycan/biosynthesis , Peptidoglycan/chemistry , Peptidoglycan/pharmacology , Microbial Sensitivity Tests , Nucleotides , Peptides , Structure-Activity Relationship , UreaABSTRACT
Twenty-five 2-phenyl-5,6-dihydro-2H-thieno[3,2-c]pyrazol-3-ol derivatives were synthesized for evaluation as new inhibitors of bacterial cell wall biosynthesis. Many of them demonstrated good inhibitory activity against Staphylococcus aureus MurB, MurC and MurD enzymes in vitro and antimicrobial activity against gram-positive bacteria including MRSA, VRE and PRSP. However, when they were tested in the presence of 4% bovine serum albumin, the MIC values increased to greater than 128 microg/mL against PRSP. None of the compounds demonstrated activity against gram-negative bacteria at MIC <32 microg/mL.
