Photoswitch dissociation from a G protein-coupled receptor resolved by time-resolved serial crystallography

Area of Science:

• Biochemistry
• Pharmacology
• Structural Biology

Background:

• G protein-coupled receptors (GPCRs) are crucial cell surface receptors and drug targets.
• Ligand binding influences GPCR conformational states, affecting function.
• Understanding GPCR-ligand dynamics is key for drug development.

Purpose of the Study:

• To investigate the dynamics of protein-ligand interactions in the human adenosine A2A receptor.
• To design and utilize photochemical affinity switches for studying receptor dynamics.
• To gain atomic-level insights into GPCR conformational changes.

Main Methods:

• Design of seven photochemical affinity switches based on istradefylline.
• Application of UV/Vis spectroscopy, time-resolved absorption spectroscopy, and differential scanning fluorimetry.
• Utilizing time-resolved serial crystallography to capture millisecond-scale dynamics.

Main Results:

• Identified istradefylline derivatives suitable for time-resolved serial crystallography.
• Observed ligand-induced trans-to-cis isomerization and pocket rearrangement.
• Demonstrated disruption of extracellular loop interactions upon ligand dissociation.

Conclusions:

• Developed an innovative method to study GPCR dynamics at the atomic level.
• Elucidated the role of ligand structure in modulating receptor pocket rearrangements.
• Provided insights for the rational design of novel GPCR-targeted pharmaceuticals.