Fluorescent pirenzepine derivatives as potential bitopic ligands of the human M1 muscarinic receptor.

Article Details

Citation

Copy to clipboard

Tahtaoui C, Parrot I, Klotz P, Guillier F, Galzi JL, Hibert M, Ilien B

Fluorescent pirenzepine derivatives as potential bitopic ligands of the human M1 muscarinic receptor.

J Med Chem. 2004 Aug 12;47(17):4300-15.

PubMed ID

15294002 [ View in PubMed

]

Abstract

Following a recent description of fluorescence resonance energy transfer between enhanced green fluorescent protein (EGFP)-fused human muscarinic M1 receptors and Bodipy-labeled pirenzepine, we synthesized seven fluorescent derivatives of this antagonist in order to further characterize ligand-receptor interactions. These compounds carry Bodipy [558/568], Rhodamine Red-X [560/580], or Fluorolink Cy3 [550/570] fluorophores connected to pirenzepine through various linkers. All molecules reversibly bind with high affinity to M1 receptors (radioligand and energy transfer binding experiments) provided that the linker contains more than six atoms. The energy transfer efficiency exhibits modest variations among ligands, indicating that the distance separating EGFP from the fluorophores remains almost constant. This also supports the notion that the fluorophores may bind to the receptor protein. Kinetic analyses reveal that the dissociation of two Bodipy derivatives (10 or 12 atom long linkers) is sensitive to the presence of the allosteric modulator brucine, while that of all other molecules (15-24 atom long linkers) is not. The data favor the idea that these analogues might interact with both the acetylcholine and the brucine binding domains.

DrugBank Data that Cites this Article

Binding Properties

Drug	Target	Property	Measurement	pH	Temperature (°C)
Pirenzepine	Muscarinic acetylcholine receptor M1	Ki (nM)	23.5	N/A	N/A	Details
Pirenzepine	Muscarinic acetylcholine receptor M1	Kd (nM)	20	N/A	N/A	Details