title: Specific and potent inhibition of NAD+-dependent DNA ligase by pyridochromanones.
abstract: Pyridochromanones were identified by high throughput screening as potent inhibitors of NAD+-dependent DNA ligase from Escherichia coli. Further characterization revealed that eubacterial DNA ligases from Gram-negative and Gram-positive sources were inhibited at nanomolar concentrations. In contrast, purified human DNA ligase I was not affected (IC50 > 75 microm), demonstrating remarkable specificity for the prokaryotic target. The binding mode is competitive with the eubacteria-specific cofactor NAD+, and no intercalation into DNA was detected. Accordingly, the compounds were bactericidal for the prominent human pathogen Staphylococcus aureus in the low microg/ml range, whereas eukaryotic cells were not affected up to 60 microg/ml. The hypothesis that inhibition of DNA ligase is the antibacterial principle was proven in studies with a temperature-sensitive ligase-deficient E. coli strain. This mutant was highly susceptible for pyridochromanones at elevated temperatures but was rescued by heterologous expression of human DNA ligase I. A physiological consequence of ligase inhibition in bacteria was massive DNA degradation, as visualized by fluorescence microscopy of labeled DNA. In summary, the pyridochromanones demonstrate that diverse eubacterial DNA ligases can be addressed by a single inhibitor without affecting eukaryotic ligases or other DNA-binding enzymes, which proves the value of DNA ligase as a novel target in antibacterial therapy.
authors.affiliation: Department of Anti-infectives, Bayer AG, Bayer Health Care, Pharma Research, Aprather Weg 18a, D-42096 Wuppertal, Germany. heike.broetz-oesterhelt.hb@bayer-ag
authors.forename: Heike
authors.initials: H
authors.lastname: Brötz-Oesterhelt
authors.forename: Igor
authors.initials: I
authors.lastname: Knezevic
authors.forename: Stephan
authors.initials: S
authors.lastname: Bartel
authors.forename: Thomas
authors.initials: T
authors.lastname: Lampe
authors.forename: Ute
authors.initials: U
authors.lastname: Warnecke-Eberz
authors.forename: Karl
authors.initials: K
authors.lastname: Ziegelbauer
authors.forename: Dieter
authors.initials: D
authors.lastname: Häbich
authors.forename: Harald
authors.initials: H
authors.lastname: Labischinski
mesh_terms: D000249:Adenosine Monophosphate / Q000378:metabolism; D001483:Base Sequence; D002839:Chromans / Q000737:chemistry / Q000494:pharmacology*; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D009154:Mutation; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D002839:Chromans; D004269:DNA, Bacterial; D004791:Enzyme Inhibitors; C000607892:LIG1 protein, human; D011994:Recombinant Proteins; D000249:Adenosine Monophosphate; D011088:DNA Ligases; D000072481:DNA Ligase ATP; C120640:DNA ligase (NAD)