# Targeting Cellular Lipid Rafts for Dynamic Nuclear Polarization Nuclear Magnetic Resonance

## TL;DR

The paper introduces a new method using DNP NMR to study lipid rafts in cells by attaching a polarizing agent to a specific protein.

## Contribution

A novel approach to target lipid rafts using DNP NMR with a raft-specific protein and polarizing agent.

## Key findings

- DNP enhancements were achieved at low concentrations of spin-labeled Ostreolysin A.
- Cross-effect efficiency is identified as a key limiting factor in lipid raft-targeted DNP.
- Fluorescence microscopy confirmed the method's specificity for lipid rafts.

## Abstract

Lipid rafts serve as important platforms for membrane and signaling proteins. The mechanisms underlying the targeting of nonmyristylated drugs and proteins to lipid rafts remain poorly understood, and the specific structural interactions that govern their localization and stabilization within these membrane microdomains are unclear. This is largely due to a lack of techniques with angstrom resolution that are capable of investigating these membrane microdomains. In‐cell nuclear magnetic resonance (NMR) spectroscopy is the only technique with the potential for obtaining such information. Here, we introduce an approach to investigate lipid rafts by in‐cell dynamic nuclear polarization (DNP) NMR by covalently linking the polarizing agent AsymPol to the raft‐specific protein Ostreolysin A (OlyA). We demonstrate the method's specificity via fluorescence microscopy and obtain DNP enhancements even at very low concentrations of spin‐labeled OlyA, whose heterogeneous localization can be identified in DNP buildup curves. Through this work, we identify cross‐effect efficiency as a key limiting factor in the pursuit of lipid raft‐targeted DNP, revealing important areas of development for enabling targeted DNP of these important cellular structures.

Illuminating lipid rafts within intact cells using dynamic nuclear polarization (DNP). Targeting lipid rafts with the protein ostreolysin A allows the selective delivery of DNP‐compatible radicals, generating hyperpolarization of nuclear spins in the lipid raft.© 2026 WILEY‐VCH GmbH