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Structural modeling reveals the allosteric switch controlling the chitin utilization program of Vibrio cholerae
Biorxiv : the Preprint Server for Biology
|September 2, 2025
Summary
Signal transduction in bacteria relies on histidine kinases (HKs) sensing environmental signals. We uncovered a novel allosteric mechanism for chitin sensing by the CBP-ChiS complex in Vibrio cholerae, distinct from known systems.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Signal transduction via histidine kinases (HKs) is crucial for bacterial adaptation.
- Solute binding protein (SBP)-dependent HK signaling mechanisms are often poorly understood.
- The chitin-binding protein (CBP) and chitin sensor (ChiS) in Vibrio cholerae regulate chitin utilization.
Purpose of the Study:
- To elucidate the molecular basis of allosteric regulation in the CBP-ChiS complex.
- To understand how ligand binding affects the interaction between CBP and ChiS.
- To explore potential conserved mechanisms in other SBP-HK systems.
Main Methods:
- Structural modeling of the CBP-ChiS complex in unliganded and liganded states.
- Extensive genetic analysis.
- Biochemical assays.
- Cell biological studies.
Main Results:
- Ligand binding induces a unique, large conformational interface switch in the CBP-ChiS complex.
- This allosteric mechanism differs from previously characterized SBP-HK systems.
- Structural models provide insights into the dynamic regulation of signal reception.
Conclusions:
- The study reveals a novel mode of allosteric regulation in bacterial signal transduction.
- Understanding the CBP-ChiS mechanism provides a framework for investigating other SBP-HK systems.
- This work expands knowledge of how bacteria sense and respond to environmental cues.
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