Oxidation of dCTP contributes to antibiotic lethality in stationary-phase mycobacteria.
Proc Natl Acad Sci U S A
; 115(9): 2210-2215, 2018 02 27.
Article
em En
| MEDLINE
| ID: mdl-29382762
ABSTRACT
Growing evidence shows that generation of reactive oxygen species (ROS) derived from antibiotic-induced metabolic perturbation contribute to antibiotic lethality. However, our knowledge of the mechanisms by which antibiotic-induced oxidative stress actually kills cells remains elusive. Here, we show that oxidation of dCTP underlies ROS-mediated antibiotic lethality via induction of DNA double-strand breaks (DSBs). Deletion of mazG-encoded 5-OH-dCTP-specific pyrophosphohydrolase potentiates antibiotic killing of stationary-phase mycobacteria, but did not affect antibiotic efficacy in exponentially growing cultures. Critically, the effect of mazG deletion on potentiating antibiotic killing is associated with antibiotic-induced ROS and accumulation of 5-OH-dCTP. Independent lines of evidence presented here indicate that the increased level of DSBs observed in the ΔmazG mutant is a dead-end event accounting for enhanced antibiotic killing. Moreover, we provided genetic evidence that 5-OH-dCTP is incorporated into genomic DNA via error-prone DNA polymerase DnaE2 and repair of 5-OH-dC lesions via the endonuclease Nth leads to the generation of lethal DSBs. This work provides a mechanistic view of ROS-mediated antibiotic lethality in stationary phase and may have broad implications not only with respect to antibiotic lethality but also to the mechanism of stress-induced mutagenesis in bacteria.
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Base de dados:
MEDLINE
Assunto principal:
Mycobacterium smegmatis
/
Nucleotídeos de Desoxicitosina
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Antibacterianos
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Mycobacterium tuberculosis
Limite:
Humans
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article