E-BUGS-115 - The minor groove-binding agent ELB-21 forms multiple interstrand and intrastrand covalent cross-links with duplex DNA and displays potent bactericidal activity against methicillin-resistant Staphylococcus aureus

Status
Released on 15 April 2011, last updated on 1 May 2014
Organism
Staphylococcus aureus
Samples (2)
Array (1)
Protocols (13)
Description
Objectives The antistaphylococcal pyrrolobenzodiazepine dimer ELB-21 forms multiple adducts with duplex DNA through covalent interactions with appropriately spaced guanine residues; it is now known to form interstrand and intrastrand adducts with oligonucleotide sequences of variable length. We determined the DNA sequence preferences of ELB-21 in relation to its capacity to exert a bactericidal effect by damaging DNA. Methods Formation of adducts by ELB-21 and 12- to 14-mer DNA duplexes was investigated using ion-pair reversed phase liquid chromatography and mass spectrometry. Drug-induced changes in gene expression were measured in prophage-free Staphylococcus aureus RN4220 by microarray analysis. Results ELB-21 preferentially formed intrastrand adducts with guanines separated by three nucleotide base pairs. Interstrand and intrastrand adducts were formed with duplexes both longer and shorter than the preferred target sequences. ELB-21 elicited rapid bactericidal effects against prophage-carrying and prophage-free S. aureus strains; cell lysis occurred following activation and release of resident prophages. Killing appeared to be due to irreparable damage to bacterial DNA and susceptibility to ELB-21 was governed by the capacity of staphylococci to repair DNA lesions through induction of the SOS DNA damage response mediated by the RecA-LexA pathway. Conclusions The data support the contention that ELB-21 arrests DNA replication, eliciting formation of ssDNA-RecA filaments that inactivate LexA, the SOS repressor, and phage repressors such as Cl, resulting in activation of the DNA damage response and de-repression of resident prophages. Above the MIC threshold, DNA repair is ineffective. Data is also available from http://bugs.sgul.ac.uk/E-BUGS-115
Experiment types
transcription profiling by array, compound treatment, replicate
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Citation
The minor groove-binding agent ELB-21 forms multiple interstrand and intrastrand covalent cross-links with duplex DNA and displays potent bactericidal activity against methicillin-resistant Staphylococcus aureus. Rosado, Helena; Rahman, Khondaker M.; Feuerbaum, Eva-Anne; Hinds, Jason; Thurston, David E.; Taylor, Peter W. FIX:Journal of Antimicrobial Chemotherapy 66(5):985 (2011), PMID:21393142
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