Stabilization versus flexibility: Detergent‐dependent trade‐offs in neurotensin receptor 1 GPCR ensembles

TL;DR

This study shows how different detergents affect the stability and flexibility of a GPCR, impacting ligand binding and signaling.

Contribution

The paper reveals a detergent-dependent trade-off between receptor stabilization and ligand-induced conformational flexibility in GPCRs.

Findings

LMNG maximizes conformational rigidity but weakens agonist binding affinity.

DM supports strong ligand-induced stabilization consistent with the engineered receptor background.

Detergent choice affects structural resolution versus dynamic characterization of GPCRs.

Abstract

Detergents provide essential membrane‐mimetic environments for studying G protein‐coupled receptors (GPCRs), but their molecular impact on receptor energetics remains incompletely understood. We combined ligand binding, thermostability measurements, and atomistic molecular dynamics to dissect detergent‐ versus ligand‐driven stabilization in a thermostabilized neurotensin receptor 1 (enNTS1). Circular dichroism and ligand binding assays revealed that apo enNTS1 becomes progressively more stable in decyl maltoside (DM), dodecyl maltoside (DDM), and lauryl maltose neopentyl glycol (LMNG). However, this gain in baseline stability was accompanied by an initially counterintuitive observation: LMNG, the most stabilizing detergent, supported the weakest neurotensin agonist binding affinity. Thermodynamic analysis shows that this behavior arises naturally from partitioning stability between detergent‐driven conformational rigidity (ΔG
conf) and ligand‐induced stabilization (ΔG
ligand). In DM, ΔG
ligand contributions were large, consistent with the receptor's engineered background. In contrast, LMNG maximized ΔG
conf, constraining conformational flexibility and reducing ΔG
ligand. Molecular dynamics simulations corroborated these results, showing that LMNG formed denser, less mobile detergent shells around the receptor, enhancing protein–detergent interaction energies while limiting conformational flexibility. Redistribution of ligand contacts, particularly at neurotensin residue Y11, further underscored detergent‐dependent modulation of the binding pocket. The results in this thermostabilized neurotensin receptor illustrate a fundamental trade‐off: LMNG provides exceptional receptor stabilization, supporting structural studies, but may mask conformational states relevant to signaling. In contrast, less rigid detergents preserve ligand‐induced transitions at the expense of stability. We therefore propose this system as a case study of how detergent chemistry can redistribute stability between conformational rigidity and ligand‐induced effects, with implications for guiding detergent choice depending on whether the goal is structural resolution or dynamic characterization.

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