Oxidation of the guanine nucleotide pool underlies cell death by bactericidal antibiotics.
A detailed understanding of the mechanisms that underlie antibiotic killing is important for the derivation of new classes of antibiotics and clinically useful adjuvants for current antimicrobial therapies. Our efforts to understand why DinB (DNA polymerase IV) overproduction is cytotoxic to Escherichia coli led to the unexpected insight that oxidation of guanine to 8-oxo-guanine in the nucleotide pool underlies much of the cell death caused by both DinB overproduction and bactericidal antibiotics. We propose a model in which the cytotoxicity of beta-lactams and quinolones predominantly results from lethal double-strand DNA breaks caused by incomplete repair of closely spaced 8-oxo-deoxyguanosine lesions, whereas the cytotoxicity of aminoglycosides might additionally result from mistranslation due to the incorporation of 8-oxo-guanine into newly synthesized RNAs.
Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
SourceScience (New York, N.Y.) 336:6079 2012 Apr 20 pg 315-9
DNA Breaks, Double-Stranded
DNA Polymerase I
DNA Polymerase II
DNA Polymerase beta
DNA-Directed DNA Polymerase
Escherichia coli Proteins
Pub Type(s)Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't