• Port-a-Patch

    Smallest patch clamp setup in the world
  • Port-a-Patch

    Easy to learn - ideal for teaching
  • Port-a-Patch

    Records from cells, organelles and bilayers
  • Port-a-Patch

    First planar patch clamp device on the market
  • Port-a-Patch

    Ideal for internal solution exchange applications

2022 - Structural basis of the negative allosteric modulation of 5-BDBD at human P2X4 receptors

icon pap   Port-a-Patch Publication in Molecular Pharmacology (2022)

Bidula S., Nadzirin I.B., Cominetti M.MD., Hickey H., Cullum S. A., Searcey M., Schmid R., Fountain S.

Molecular Pharmacology (2022) doi:10.1124/molpharm.121.000402


The P2X4 receptor is a ligand-gated ion channel activated by extracellular ATP. P2X4 activity is associated with neuropathic pain, vasodilation, and pulmonary secretion and is therefore of therapeutic interest. The structure-activity relationship of P2X4 antagonists is poorly understood. Here we elucidate the structure-activity of 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one (5-BDBD) at human P2X4 by combining pharmacology, electrophysiology, molecular modeling, and medicinal chemistry. 5-BDBD antagonized P2X4 in a noncompetitive manner but lacked effect at human P2X2. Molecular modeling and site-directed mutagenesis suggested an allosteric binding site for 5-BDBD located between two subunits in the body region of P2X4, with M109, F178, Y300, and I312 on one subunit and R301 on the neighboring subunit as key residues involved in antagonist binding. The bromine group of 5-BDBD was redundant for the antagonist activity of 5-BDBD, although an interaction between the carbonyl group of 5-BDBD and R301 in P2X4 was associated with 5-BDBD activity. 5-BDBD could inhibit the closed channel but poorly inhibited the channel in the open/desensitizing state. We hypothesize that this is due to constriction of the allosteric site after transition from closed to open channel state. We propose that M109, F178, Y300, R301, and I312 are key residues for 5-BDBD binding; provide a structural explanation of how they contribute to 5-BDBD antagonism; and highlight that the limited action of 5-BDBD on open versus closed channels is due to a conformational change in the allosteric site.

Download here

Back to Overview

We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.