Applications

EPR spectroscopy is a powerful tool for probing protein dynamics.

EPR measurements provide valuable structural information on biomolecules like proteins and nucleotides in a variety of environments using small sample quantities. Researchers are able to label amino acids in a site-specific manner with paramagnetic reporter groups, enabling ligand binding dynamics and protein-protein interactions to be probed by EPR techniques.

High Q offers next-generation quantum-enabled EPR spectrometers with comprehensive applications support.

High Q’s applications lab will open for visitors in 2023.

The importance of EPR in Protein Dynamics

Ligand-induced protein conformational changes

The higher sensitivity provided by High Q's EPR systems better reveals the conformational equilibrium of proteins in near-native environments.

Conformation screening prior to Cryo EM

Before determining structures with Cryo EM, EPR can be used as a screening tool to effectively search for optimal sample conditions. The speed improvements provided by High Q's EPR systems enable researchers to quickly screen for optimal sample conditions, maximizing the value of Cryo EM measurements.

Protein-Protein complex mapping

The sensitivity improvements provided by High Q's EPR systems allow lower protein concentrations to be used for dipolar distance measurements, providing experimental constraints for molecular dynamics simulations.

Intrinsically Disordered Proteins (IDPs)

A significant advantage of EPR is the ability to measure intrinsically disordered proteins of all sizes. High Q's sensitive EPR systems allow dilute protein samples to be studied, avoiding challenges associated with aggregation.

Publications highlighting applications of modern EPR spectroscopy in structural biology:

Electron paramagnetic resonance spectroscopy on G-protein–coupled receptors: Adopting strategies from related model systems
Reichenwallner, J., Liu, B., Balo, A., Ou, W. & Ernst, O. Electron paramagnetic resonance spectroscopy on G-protein-coupled receptors: Adopting strategies from related model systems. Current Opinion in Structural Biology 69, 177-186 (2021).

Abstract: Membrane proteins, including ion channels, transporters and G-protein-coupled receptors (GPCRs), play a significant role in various physiological processes. Many of these proteins are difficult to express in large quantities, imposing crucial experimental restrictions. Nevertheless, there is now a wide variety of studies available utilizing electron paramagnetic resonance (EPR) spectroscopic techniques that expand experimental accessibility by using relatively small quantities of protein…Read full opinion here.

DEER analysis of GPCR conformational heterogeneity
Elgeti, M. & Hubbell, W. DEER Analysis of GPCR Conformational Heterogeneity. Biomolecules 11, 778 (2021).

Abstract: G protein-coupled receptors (GPCRs) represent a large class of transmembrane helical proteins which are involved in numerous physiological signaling pathways and therefore represent crucial pharmacological targets. GPCR function and the action of therapeutic molecules are defined by only a few parameters, including receptor basal activity, ligand affinity, intrinsic efficacy and signal bias. These parameters are encoded in characteristic receptor conformations existing in equilibrium and their populations, which are thus of paramount interest for the understanding of receptor (mal-)functions and rational design of improved therapeutics…Read full opinion here.

The contribution of modern EPR to structural biology
Jeschke, G. The contribution of modern EPR to structural biology. Emerging Topics in Life Sciences 2, 9-18 (2018).

Abstract: Electron paramagnetic resonance (EPR) spectroscopy combined with site-directed spin labelling is applicable to biomolecules and their complexes irrespective of system size and in a broad range of environments. Neither short-range nor long-range order is required to obtain structural restraints on accessibility of sites to water or oxygen, on secondary structure, and on distances between sites. Many of the experiments characterize a static ensemble obtained by shock-freezing…Read full opinion here.