RESUMO
The bacterial toxin CcdB (Controller of Cell death or division B) targets DNA Gyrase, an essential bacterial topoisomerase, which is also the molecular target for fluoroquinolones. Here, we present a short cell-penetrating 24-mer peptide, CP1-WT, derived from the Gyrase-binding region of CcdB and examine its effect on growth of Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus and a carbapenem- and tigecycline-resistant strain of Acinetobacter baumannii in both axenic cultures and mouse models of infection. The CP1-WT peptide shows significant improvement over ciprofloxacin in terms of its in vivo therapeutic efficacy in treating established infections of S. Typhimurium, S. aureus and A. baumannii. The molecular mechanism likely involves inhibition of Gyrase or Topoisomerase IV, depending on the strain used. The study validates the CcdB binding site on bacterial DNA Gyrase as a viable and alternative target to the fluoroquinolone binding site.
Assuntos
Antibacterianos , Staphylococcus aureus , Animais , Camundongos , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Antibacterianos/farmacologia , DNA Girase/química , DNA Girase/genética , DNA Girase/metabolismo , DNA Topoisomerase IV/genética , DNA Topoisomerase IV/metabolismo , DNA Topoisomerase IV/farmacologia , Peptídeos/farmacologiaRESUMO
Bacterial topoisomerase IV (ParE) is essential for DNA replication and serves as an attractive target for antibacterial drug development. The X-ray structure of the N-terminal 24 kDa ParE, responsible for ATP binding has been solved. Due to the accessibility of structural information of ParE, many potent ParE inhibitors have been discovered. In this study, a pyridylurea lead molecule against ParE of Escherichia coli (eParE) was characterized with a series of biochemical and biophysical techniques. More importantly, solution NMR analysis of compound binding to eParE provides better understanding of the molecular interactions between the inhibitor and eParE.
Assuntos
Trifosfato de Adenosina/metabolismo , DNA Topoisomerase IV/metabolismo , DNA Topoisomerase IV/farmacologia , Escherichia coli/enzimologia , Trifosfato de Adenosina/antagonistas & inibidores , Sequência de Aminoácidos , Antibacterianos/farmacologia , Ligação Competitiva , DNA Topoisomerase IV/antagonistas & inibidores , DNA Topoisomerase IV/química , Desenho de Fármacos , Dados de Sequência Molecular , Ressonância Magnética Nuclear BiomolecularRESUMO
In human tumors, p53 inactivation occurs frequently by mutation, and possibly also by nuclear exclusion of wt p53. First reported by Uta Moll in 1992, p53 "cytoplasmic sequestration" has been thoroughly studied to elucidate molecular mechanism of this process, using neuroblastoma cell lines as model. An American team at the Columbia University has just isolated the cytoplasmic protein Parc [Nikolaev, Cell] which specifically binds to p53 and anchors it, so that the "guardian of the genome" cannot play its role in the nucleus. AntiParc siRNA-manipulation relocates p53 into the nucleus, restitutes a function to p and chemo-radiosensitivity to malignant neuroblasts.