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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
The SrrAB two-component system regulates Staphylococcus aureus pathogenicity through redox sensitive cysteines.
Nitija Tiwari1, Marisa López-Redondo2,3, Laura Miguel-Romero2,3
1Department of Biochemistry, University of Iowa, Iowa City, IA 52242.
The SrrAB two-component system (TCS) regulates Staphylococcus aureus virulence. A unique disulfide bond in SrrB senses redox signals, controlling bacterial survival and pathogenesis during infection.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Staphylococcus aureus causes diverse diseases, from skin infections to toxic shock syndrome.
- The SrrAB two-component system (TCS) is crucial for S. aureus virulence and survival under various environmental stresses.
- The sensing and response mechanisms of SrrAB to environmental signals are not fully understood.
Purpose of the Study:
- To elucidate the mechanism by which the SrrAB TCS senses environmental signals.
- To investigate the role of specific domains within the SrrB histidine kinase.
- To determine the impact of SrrB regulation on S. aureus pathogenesis.
Main Methods:
- Bioinformatics analysis of SrrB domains.
- Structural determination of the SrrB DHp-CA catalytic core.
- In vitro enzyme activity assays.
- In vivo studies using a rabbit infective endocarditis model.
Main Results:
- The PAS domain of SrrB regulates its kinase and phosphatase activity.
- A unique intramolecular disulfide bond was identified in the SrrB ATP-binding domain, affecting autophosphorylation.
- The redox state of the disulfide bond influences S. aureus biofilm formation and toxin production.
- This disulfide bond is critical for SrrB function during S. aureus infection in a rabbit model.
Conclusions:
- The disulfide bond and PAS domain of SrrB act as redox sensors.
- SrrB integrates environmental redox signals to regulate S. aureus survival and pathogenesis.
- This provides a novel mechanism for bacterial adaptation and virulence regulation.
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