Related Experiment Video
Updated: May 10, 2025
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Quantification of Bacterial Histidine Kinase Autophosphorylation Using a Nitrocellulose Binding Assay
Published on: January 11, 2017
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Allosteric coupling activation mechanism in histidine kinases
Juan Cruz Almada1, Ana Bortolotti1, Lucía Porrini1
1Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, CONICET, Rosario, Argentina.
Scientific Reports
|April 26, 2025
Summary
Histidine kinases (HKs) can activate gene expression without phosphorylation. A novel allosteric mechanism, independent of ATP, was discovered in Bacillus subtilis DesK and Escherichia coli EnvZ.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Histidine kinases (HKs) are key regulators of cellular processes via phosphorylation.
- They typically activate response regulators (RRs) by transferring a phosphate group from ATP to a conserved histidine residue.
Purpose of the Study:
- To investigate the signal transduction mechanism of Bacillus subtilis HK DesK.
- To explore alternative pathways for RR activation independent of histidine phosphorylation.
Main Methods:
- Site-directed mutagenesis of the conserved phospho-acceptor histidine in DesK.
- In vivo and in vitro assays to evaluate DesK activity.
- Computational simulations of DesK-DesR complexes.
- Testing Escherichia coli HK EnvZ variants.
Main Results:
- A DesK variant lacking the conserved histidine retained the ability to activate gene expression.
- Computational modeling revealed potential allosteric interactions maintaining RR active conformation.
- Escherichia coli EnvZ also activated gene expression without its conserved histidine.
Conclusions:
- An alternative, non-phosphorylative pathway for RR activation exists, termed HK-Allosteric Coupling Activation Mechanism.
- This mechanism is independent of ATP consumption and may function as a fail-safe under nutrient limitation.
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