YbiB: a novel interactor of the GTPase ObgE.

Obg is a widely conserved and essential GTPase in bacteria, which plays a central role in a large range of important cellular processes, such as ribosome biogenesis, DNA replication, cell division and bacterial persistence. Nevertheless, the exact function of Obg in these processes and the interactions it makes within the associated pathways remain largely unknown. Here, we identify the DNA-binding TrpD2 protein YbiB as an interactor of the Escherichia coli Obg (ObgE).

The Dynamic Transition of Persistence toward the Viable but Nonculturable State during Stationary Phase Is Driven by Protein Aggregation.

Decades of research into bacterial persistence has been unable to fully characterize this antibiotic-tolerant phenotype, thereby hampering the development of therapies effective against chronic infections. Although some active persister mechanisms have been identified, the prevailing view is that cells become persistent because they enter a dormant state. We therefore characterized starvation-induced dormancy in Escherichia coli.

GTP Binding is Necessary for the Activation of a Toxic Mutant Isoform of the Essential GTPase ObgE.

Even though the Obg protein is essential for bacterial viability, the cellular functions of this universally conserved GTPase remain enigmatic. Moreover, the influence of GTP and GDP binding on the activity of this protein is largely unknown. Previously, we identified a mutant isoform of ObgE (the Obg protein of ) that triggers cell death.

Biochemical determinants of ObgE-mediated persistence.

Obg is a versatile GTPase that plays a pivotal role in bacterial persistence. We previously showed that the Escherichia coli homolog ObgE exerts this activity through transcriptional activation of a toxin-antitoxin module and subsequent membrane depolarization. Here, we assessed the role of G-domain functionality in ObgE-mediated persistence.

Reactive oxygen species do not contribute to ObgE*-mediated programmed cell death.

Programmed cell death (PCD) in bacteria is considered an important target for developing novel antimicrobials. Development of PCD-specific therapies requires a deeper understanding of what drives this process. We recently discovered a new mode of PCD in Escherichia coli that is triggered by expression of a mutant isoform of the essential ObgE protein, ObgE*.