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Analyzing ligand and small molecule binding activity of solubilized GPCRs using biosensor technology
Iva Navratilova1, Marianna Dioszegi, David G Myszka
1Center for Biomolecular Interaction Analysis, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
Analytical Biochemistry
|June 10, 2006
Summary
This study demonstrates that solubilized chemokine receptors CXCR4 and CCR5 retain native binding properties for ligands and small molecules. This validates biosensor assays for drug discovery and structural analysis of these G protein-coupled receptors.
Area of Science:
- Biochemistry
- Pharmacology
- Molecular Biology
Background:
- Chemokine receptors CXCR4 and CCR5 are critical targets for various diseases, including HIV and cancer.
- Studying these G protein-coupled receptors (GPCRs) requires methods that preserve their native binding characteristics.
- Previous methods for studying receptor-ligand interactions often involved membrane-bound receptors, posing challenges for detailed biophysical and structural analysis.
Purpose of the Study:
- To develop and validate a biosensor assay using solubilized chemokine receptors CXCR4 and CCR5.
- To assess the binding affinity of natural ligands and small molecules to these receptors.
- To demonstrate the utility of solubilized receptors for kinetic characterization and structural studies.
Main Methods:
- Utilized Biacore technology for direct measurement of binding interactions.
- Solubilized chemokine receptors (CXCR4 and CCR5) from whole cell pellets.
- Captured solubilized receptors on antibody surfaces for biosensor analysis.
- Validated the assay using known ligands (SDF-1alpha, RANTES) and small molecule inhibitors (RCP-168, JM-2987, TAK-779).
Main Results:
- Solubilization conditions successfully maintained high-affinity binding of natural ligands to CXCR4 and CCR5.
- The biosensor assay demonstrated reliable binding responses for both chemokines and small molecule inhibitors.
- High-quality kinetic data were obtained for 19 novel small molecule inhibitors of CCR5, correlating with membrane-associated receptor values.
- Demonstrated the ability to collect binding responses for archetypal small molecule inhibitors.
Conclusions:
- Solubilized chemokine receptors CXCR4 and CCR5 retain their native binding properties.
- The developed biosensor-based method is effective for characterizing ligand and small molecule interactions with these receptors.
- These solubilized receptor preparations are valuable reagents for future biophysical and structural investigations of chemokine receptors.
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