Related Experiment Videos
Mouse brain opioid receptor identification by direct ultraviolet photoaffinity labeling
K Nagamatsu1, Y Tagawa, S Uchida
1Nihon University, College of Pharmacy, Chiba, Japan.
Biochemical Pharmacology
|October 5, 1993
Summary
Researchers used UV light to directly link radiolabeled opiates to mouse brain opiate receptors. This photoaffinity labeling identified a 58 kDa protein and revealed covalent binding between [3H]DPDPE and delta-opioid receptors.
Area of Science:
- Neuroscience
- Biochemistry
- Pharmacology
Background:
- Opiate receptors are crucial targets for pain management.
- Understanding their molecular structure is key to developing new analgesics.
- Photoaffinity labeling offers a method to study receptor-ligand interactions.
Purpose of the Study:
- To characterize mouse brain opiate receptors using direct UV-photoaffinity labeling.
- To identify specific proteins within the opiate receptor complex.
- To investigate the binding mechanism of different opiate ligands.
Main Methods:
- Direct UV (254 nm) photoaffinity labeling of mouse brain membranes with radiolabeled opiates: [3H]Morphine, [3H]PL-017, and [3H]DPDPE.
- Analysis of labeled proteins by SDS-PAGE and assessment of ligand specificity using naloxone.
- Investigation of the role of disulfide bonds using dithiothreitol and analysis of amino acid residues via acid hydrolysis.
Main Results:
- [3H]Morphine specifically labeled a 58 kDa protein, with labeling inhibited by naloxone.
- Dithiothreitol decreased irreversible binding of [3H]morphine and [3H]PL-017.
- Acid hydrolysis of [3H]DPDPE-labeled receptors revealed dityrosine, suggesting covalent binding to a tyrosine residue on delta-opioid receptors.
Conclusions:
- Direct UV-photoaffinity labeling is effective for characterizing opiate receptors.
- A 58 kDa protein is a component of the mouse brain opiate receptor complex.
- [3H]DPDPE covalently binds to a tyrosine residue in delta-opioid receptors.