# Detection of an Antagonist Bound to the Neurokinin a Receptor in Styrene–Maleic Acid Lipid Particles by 19F Ultrafast Magic‐Angle Spinning Nuclear Magnetic Resonance Spectroscopy

## TL;DR

Scientists used a special NMR technique to detect a drug-like molecule bound to a brain receptor in a new kind of lipid particle.

## Contribution

The study demonstrates the use of 19F ultrafast MAS NMR to detect ligand-receptor interactions in detergent-free lipid particles.

## Key findings

- 19F NMR detected distinct ligand populations in SMALPs.
- The fluorinated antagonist GR159897 was shown to bind to the neurokinin A receptor.
- The method enables detailed study of GPCR-ligand interactions in native-like membranes.

## Abstract

G protein‐coupled receptors (GPCRs) are major pharmacological targets, with ≈34% of FDA‐approved drugs acting on this protein family. The frequent incorporation of fluorine into small‐molecule ligands enables the use of 19F nuclear magnetic resonance (NMR) as a sensitive and site‐specific method to probe ligand behaviour. In this case study, we investigate the fluorinated antagonist GR159897 bound to the membrane‐embedded neurokinin A receptor reconstituted in detergent‐free styrene–maleic acid lipid particles (SMALPs) using 19F ultrafast magic‐angle spinning (MAS) solid‐state NMR. We demonstrate that the environmental sensitivity of 19F NMR resolves distinct ligand populations within the SMALP system and enables detection of receptor‐associated ligand, highlighting the utility of 19F solid‐state NMR for probing GPCR–ligand interactions.

The detection of a fluorinated antagonist bound to the neurokinin A receptor by 19F ultrafast MAS NMR is demonstrated. Therefore, the receptor is purified by detergent‐free extraction by styrene maleic acid copolymer encapsulation and subsequently characterised.© 2026 WILEY‐VCH GmbH