@article{Rasmussen2023,
  author    = {Rasmussen, Tim},
  title     = {The potassium efflux system Kef: bacterial protection against toxic electrophilic compounds},
  series = {Membranes},
  volume    = {13},
  journal   = {Membranes},
  number    = {5},
  issn      = {2077-0375},
  doi       = {10.3390/membranes13050465},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313686},
  year      = {2023},
  abstract  = {Kef couples the potassium efflux with proton influx in gram-negative bacteria. The resulting acidification of the cytosol efficiently prevents the killing of the bacteria by reactive electrophilic compounds. While other degradation pathways for electrophiles exist, Kef is a short-term response that is crucial for survival. It requires tight regulation since its activation comes with the burden of disturbed homeostasis. Electrophiles, entering the cell, react spontaneously or catalytically with glutathione, which is present at high concentrations in the cytosol. The resulting glutathione conjugates bind to the cytosolic regulatory domain of Kef and trigger activation while the binding of glutathione keeps the system closed. Furthermore, nucleotides can bind to this domain for stabilization or inhibition. The binding of an additional ancillary subunit, called KefF or KefG, to the cytosolic domain is required for full activation. The regulatory domain is termed K+ transport-nucleotide binding (KTN) or regulator of potassium conductance (RCK) domain, and it is also found in potassium uptake systems or channels in other oligomeric arrangements. Bacterial RosB-like transporters and K+ efflux antiporters (KEA) of plants are homologs of Kef but fulfill different functions. In summary, Kef provides an interesting and well-studied example of a highly regulated bacterial transport system.},
  language  = {en}
}
@article{IbrahimOhlsen2022,
  author    = {Ibrahim, Eslam S. and Ohlsen, Knut},
  title     = {The old yellow enzyme OfrA fosters Staphylococcus aureus survival via affecting thiol-dependent redox homeostasis},
  series = {Frontiers in Microbiology},
  volume    = {13},
  journal   = {Frontiers in Microbiology},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2022.888140},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-274381},
  year      = {2022},
  abstract  = {Old yellow enzymes (OYEs) are widely found in the bacterial, fungal, and plant kingdoms but absent in humans and have been used as biocatalysts for decades. However, OYEs' physiological function in bacterial stress response and infection situations remained enigmatic. As a pathogen, the Gram-positive bacterium Staphylococcus aureus adapts to numerous stress conditions during pathogenesis. Here, we show that in S. aureus genome, two paralogous genes (ofrA and ofrB) encode for two OYEs. We conducted a bioinformatic analysis and found that ofrA is conserved among all publicly available representative staphylococcal genomes and some Firmicutes. Expression of ofrA is induced by electrophilic, oxidative, and hypochlorite stress in S. aureus. Furthermore, ofrA contributes to S. aureus survival against reactive electrophilic, oxygen, and chlorine species (RES, ROS, and RCS) via thiol-dependent redox homeostasis. At the host-pathogen interface, S. aureusΔofrA has defective survival in macrophages and whole human blood and decreased staphyloxanthin production. Overall, our results shed the light onto a novel stress response strategy in the important human pathogen S. aureus.},
  language  = {en}
}