Response of Staphylococcus aureus to subinhibitory concentrations of a sequence-selective, DNA minor groove cross-linking pyrrolobenzodiazepine dimer


Doyle, M., Feuerbaum, E.-A., Fox, Keith R., Hinds, J., Thurston, D. E. and Taylor, P. W. (2009) Response of Staphylococcus aureus to subinhibitory concentrations of a sequence-selective, DNA minor groove cross-linking pyrrolobenzodiazepine dimer. Journal of Antimicrobial Chemotherapy, 64, (5), 949-959. (doi:10.1093/jac/dkp325).

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Description/Abstract

Objectives ELB-21 is a pyrrolo[2,1-c][1,4]benzodiazepine dimer with potent antistaphylococcal activity; it binds covalently to guanine residues on opposing strands of duplex DNA, interfering with regulatory proteins and transcription elongation in a sequence-selective manner. Transcriptional and proteomic alterations induced by exposure of Staphylococcus aureus clinical isolate EMRSA-16 to ELB-21 were determined in order to define more precisely the bactericidal mechanism of the drug.
Methods DNase I footprinting was used to identify high-affinity DNA binding sites. Microarrays and gel electrophoresis were used to assess the ELB-21-induced phenotype.
Results High-affinity interstrand binding sites in which guanine residues were separated by 4 bp, and also some intrastrand cross-linking sites of variable length were identified. Exposure of EMRSA-16 to 0.015 mg/L ELB-21 elicited a 2-fold or greater up-regulation of 168 genes in logarithmic phase and 181 genes in stationary phase; the majority of genes affected were associated with resident prophages ϕSa2 and ϕSa3, pathogenicity island SaPI4 and DNA damage repair. ELB-21 induced a marked increase in the number of viable phage particles in culture supernatants. The expression of only a limited number of genes showed a >50% reduction. Sixteen extracellular and four intracellular proteins were differentially expressed during logarithmic and stationary phases, including RecA, proteins associated with staphylococcal pathogenesis (IsaA, CspA), cell division and wall synthesis.
Conclusions ELB-21 kills S. aureus by forming multiple interstrand and intrastrand DNA cross-links, resulting in induction of the DNA damage response, derepression of resident prophages and modulation of a limited number of genes involved with cell wall synthesis.

Item Type: Article
ISSNs: 0305-7453 (print)
1460-2091 (electronic)
Related URLs:
Subjects: Q Science > QD Chemistry
Divisions: Faculty of Natural and Environmental Sciences > Biological Sciences > Molecular & Cellular
ePrint ID: 206543
Date Deposited: 22 Dec 2011 15:31
Last Modified: 27 Mar 2014 19:49
URI: http://eprints.soton.ac.uk/id/eprint/206543

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