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Updated: Jun 6, 2026
10:59
Visualizing the Conformational Dynamics of Membrane Receptors Using Single-Molecule FRET
Published on: August 17, 2022
Chemoreceptors in signalling complexes: shifted conformation and asymmetric coupling
Divya N Amin1, Gerald L Hazelbauer
1Department of Biochemistry, 117 Schweitzer Hall, University of Missouri-Columbia, Columbia, MO 65211, USA.
Molecular Microbiology
|November 25, 2010
Summary
Bacterial chemotaxis signaling complexes tune chemoreceptors for higher sensitivity by shifting conformation. Asymmetrical coupling between receptors and kinase reveals new mechanisms for precise sensory adaptation.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Bacterial chemotaxis relies on signaling complexes involving chemoreceptors, histidine kinase CheA, and CheW.
- Interactions within these complexes significantly influence kinase activity and receptor function.
Purpose of the Study:
- To investigate the effects of signaling complex interactions on chemoreceptor conformation and signaling.
- To compare receptor behavior alone versus within complexes.
Main Methods:
- Assays of initial methylation rates to determine receptor conformational states.
- Comparison of receptor behavior in isolation and within signaling complexes.
Main Results:
- Signaling complexes shift chemoreceptors to a methylation-on, higher-ligand-affinity, kinase-off state, enhancing sensitivity.
- Transmembrane and conformational signaling within receptors remained largely unaltered.
- Ligand binding cooperatively affects kinase activity, with a >100-fold dynamic range expansion via adaptational modification.
- Receptor modification increases dynamic range stepwise, affecting ligand-to-receptor and receptor-to-kinase coupling.
Conclusions:
- Interactions within signaling complexes lead to asymmetrical coupling between chemoreceptors and kinase.
- This asymmetry has implications for the precise adaptation mechanisms in bacterial chemotaxis.
- Variable coupling presents a novel control point for sensory regulation.
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