title: An O2-sensing stressosome from a Gram-negative bacterium.
abstract: Bacteria have evolved numerous pathways to sense and respond to changing environmental conditions, including, within Gram-positive bacteria, the stressosome complex that regulates transcription of general stress response genes. However, the signalling molecules recognized by Gram-positive stressosomes have yet to be identified, hindering our understanding of the signal transduction mechanism within the complex. Furthermore, an analogous pathway has yet to be described in Gram-negative bacteria. Here we characterize a putative stressosome from the Gram-negative bacterium Vibrio brasiliensis. The sensor protein RsbR binds haem and exhibits ligand-dependent control of the stressosome complex activity. Oxygen binding to the haem decreases activity, while ferrous RsbR results in increased activity, suggesting that the V. brasiliensis stressosome may be activated when the bacterium enters anaerobic growth conditions. The findings provide a model system for investigating ligand-dependent signalling within stressosome complexes, as well as insights into potential pathways controlled by oxygen-dependent signalling within Vibrio species.
authors.affiliation: Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Jia
authors.affiliation: Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
authors.forename: Jian-Bo
authors.initials: JB
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
authors.forename: Shannon
authors.initials: S
authors.lastname: Rivera
authors.affiliation: Integrated Proteomics Core, Emory University, 615 Michael Street, Atlanta, Georgia 30322, USA.
authors.forename: Duc
authors.initials: D
authors.lastname: Duong
authors.affiliation: Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Weinert
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D006418:Heme / Q000378:metabolism; D007700:Kinetics; D008024:Ligands; D008954:Models, Biological; D008958:Models, Molecular; D010100:Oxygen / Q000378:metabolism*; D010316:Particle Size; D010766:Phosphorylation; D013312:Stress, Physiological; D014733:Vibrio / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D008024:Ligands; D006418:Heme; D010100:Oxygen