Bacterial Toxin-Antitoxin Systems as Targets for the Development of Novel Antibiotics

Abstract

This chapter focuses on the proteic toxin-antitoxin (TA) systems. TA systems function as vitally important regulatory systems in bacteria and represent ideal targets for the development of novel antibiotic therapeutic agents. A broad mechanistic understanding of TA systems at physiological, biochemical, biophysical, and structural levels provides the scientific framework needed both for rational drug design and for elegant selection schemes using large pools of compounds. The proteins of chromosome-encoded TA systems (relBE, yefM-yoeB, and dinJ-yafQ) from gram-negative bacteria, namely, CcdA-CcdB, Phd-Doc, ParD-ParE, YefM-YoeB, and one system from a plasmid from a G+ bacterium, have been studied in vitro with respect to their properties in solution and binding to DNA. The chapter summarizes the knowledge accumulated on these proteins. Pathogenic bacteria are subjected to an enormous selective pressure because of the indiscriminate overuse and misuse of broad-spectrum antibiotics. The recognition of the importance of protein-protein interactions within the cell has led to their investigation as targets for novel inhibitors. Here, the approaches that can be used for screening of inhibitors of protein-protein interactions are highlighted by recent research on the TA systems. The chapter focuses on two resonance energy transfer techniques, namely, fluorescent resonance energy transfer (FRET) and, especially, bioluminescence resonance energy transfer (BRET), since they have demonstrated to be highly useful for studying interactions between two proteins that have been shown to form complexes.