Novel Gram-positive (Gram+) antibacterial compounds consisting of a DNA polymerase IIIC (pol IIIC) inhibitor covalently connected to a topoisomerase/gyrase inhibitor are described. Specifically, 3-substituted 6-(3-ethyl-4-methylanilino)uracils (EMAUs) in which the 3-substituent is a fluoroquinolone moiety (FQ) connected by various linkers were synthesized. The resulting "AU-FQ" hybrid compounds were significantly more potent than the parent EMAU compounds as inhibitors of pol IIIC and were up to 64-fold more potent as antibacterials in vitro against Gram+ bacteria. The hybrids inhibited the FQ targets, topoisomerase IV and gyrase, with potencies similar to norfloxacin but 10-fold lower than newer agents, for example, ciprofloxacin and sparfloxacin. Representative hybrids protected mice from lethal Staphylococcus aureus infection after intravenous dosing, and one compound showed protective effect against several antibiotic-sensitive and -resistant Gram+ infections in mice. The AU-FQ hybrids are a promising new family of antibacterials for treatment of antibiotic-resistant Gram+ infections.
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http://dx.doi.org/10.1021/jm0510023 | DOI Listing |
Nucleic Acids Res
January 2025
Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Transcription of transfer RNA (tRNA) genes by RNA polymerase (Pol) III requires the general transcription factor IIIC (TFIIIC), which recognizes intragenic A-box and B-box DNA motifs of type II gene promoters. However, the underlying mechanism has remained elusive, in part due to missing structural information for A-box recognition. In this study, we use single-particle cryogenic electron microscopy (cryo-EM) and single-molecule fluorescence resonance energy transfer (smFRET) to reveal structural and real-time kinetic insights into how the 520-kDa yeast TFIIIC complex engages A-box and B-box DNA motifs in the context of a tRNA gene promoter.
View Article and Find Full Text PDFBackground: Ibezapolstat (IBZ) is a competitive inhibitor of the bacterial Pol IIIC enzyme in clinical development for treatment of infection (CDI). Previous studies demonstrated IBZ carries a favorable microbiome diversity profile compared to vancomycin (VAN). However, head-to-head comparisons with other CDI antibiotics have not been done.
View Article and Find Full Text PDFHum Genet
March 2024
Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
General transcription factor IIIC subunit 5 (GTF3C5) encodes transcription factor IIIC63 (TFIIIC63). It binds to DNA to recruit another transcription factor, TFIIIB, and RNA polymerase III (Pol III) to mediate the transcription of small noncoding RNAs, such as tRNAs. Here, we report four individuals from three families presenting with a multisystem developmental disorder phenotype with biallelic variants in GTF3C5.
View Article and Find Full Text PDFSci Adv
July 2023
Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Transcription factor (TF) IIIC recruits RNA polymerase (Pol) III to most of its target genes. Recognition of intragenic A- and B-box motifs in transfer RNA (tRNA) genes by TFIIIC modules τA and τB is the first critical step for tRNA synthesis but is mechanistically poorly understood. Here, we report cryo-electron microscopy structures of the six-subunit human TFIIIC complex unbound and bound to a tRNA gene.
View Article and Find Full Text PDFACS Infect Dis
April 2022
Chemistry Department, Institute for Drug Discovery, Purdue University, West Lafayette, Indiana 47907, United States.
Drug-resistant bacterial pathogens still cause high levels of mortality annually despite the availability of many antibiotics. Methicillin-resistant (MRSA) is especially problematic, and the rise in resistance to front-line treatments like vancomycin and linezolid calls for new chemical modalities to treat chronic and relapsing MRSA infections. Halogenated -(1,3,4-oxadiazol-2-yl)benzamides are an interesting class of antimicrobial agents, which have been described by multiple groups to be effective against different bacterial pathogens.
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