Abstract

The Angiotensin II Receptor Type 1 (AT1R), a critical G protein-coupled receptor (GPCR) in the renin-angiotensin-aldosterone system, is a major pharmacological target for hypertension and cardiovascular disease. However, its inherent instability and low expression levels in heterologous systems present significant challenges for high-resolution biophysical and structural studies. This manuscript details the **optimization of a robust production protocol** for the AT1R, a necessary prerequisite for advanced structural and functional characterization. We employed a baculovirus expression system in insect cells, systematically varying parameters such as construct design, detergent screening for solubilization, and chromatographic conditions for purification. The optimized protocol yielded milligram quantities of highly pure, functionally active AT1R, confirmed by ligand binding assays and thermal stability measurements. The resulting high-quality protein is suitable for techniques such as X-ray crystallography, cryo-electron microscopy, and nuclear magnetic resonance. This optimized method represents a significant technical advance, facilitating future studies into the molecular mechanisms of AT1R activation and allosteric modulation, which is vital for the rational design of next-generation therapeutics.