Optimizing Structural Characterization of the G-Protein Coupled Estrogen Receptor (GPER-1): Applying a Validated Cryo-EM Pipeline to the Novel Agonist CIFTA for Targeted Oncology

Authors: Peter Zavack, Olivia Stebbins, Grace Coulter

Field of Study: Chemistry; Integrative Neuroscience

Program Affiliation: Dr. Su Lab

Faculty Mentors: Minfei Su, Olivia Stebbins, Grace Coulter

Easel: 71

Timeslot: Midday

Abstract: GPER-1 is a critical GPCR target in metastatic breast cancer. This study outlines the purification and structural characterization of the a GPER-1 complex bound to the novel agonist CIFTA. Using anti-GFP affinity chromatography and a validated Cryo-EM pipeline, the GPER-1-Gq-scFv16 quaternary signaling complex was isolated. Since purification is central to this approach, structural purity was verified through Size-Exclusion Chromatography (SEC) and SDS-PAGE. SEC profiles demonstrated high sample homogeneity, with a primary elution peak at ~11 mL. Supporting gel images confirmed the successful co-expression of all essential protein subunits. Benchmarked against 17-estradiol (4.0-6.2 Å), this optimized framework enables high-resolution structural mapping of CIFTA’s unique binding pocket. These results provide the necessary background data to support “Structure-Based Drug Design” (SBDD), facilitating the creation of selective ligands for targeted oncology and neuroprotection.