Recombinant Extracellular Domain Proteins
High-purity, authentically folded soluble receptor domains and cell-surface antigens for antibody discovery, aptamer selection, and drug development.
Recombinant Protein Science
Authentic human post-translational modifications and folding
Cell-surface receptor extracellular domains (ECDs) play pivotal roles in intercellular signaling, immunological defense, and viral entry. Producing soluble, biologically active ECD targets requires careful signal peptide engineering, correct disulfide pairing, and mammalian post-translational glycosylation.
At RNA Nanorobotics, our protein production suite combines transient mammalian suspension culture in VWR® 190 L CO₂ shakers with automated multi-step chromatography on our GE Healthcare ÄKTA pure 25 FPLC platform. We deliver monodisperse, endotoxin-depleted ECD proteins ready for SPR binding assays, SELEX aptamer campaigns, or structural biology.
Production Workflow
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1
Construct Engineering: Signal peptide prediction, boundary definition, and codon optimization for high-titer secretory expression.
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2
Host Expression: High-density culture in Expi293F (serum-free mammalian) or Sf9 insect cells with controlled CO₂ and agitation.
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3
ÄKTA pure FPLC Polishing: Affinity capture followed by preparative size-exclusion chromatography (SEC) to isolate monomeric species from aggregates.
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Analytical QC: SDS-PAGE on Bio-Rad PowerPac, Azure 2000 digital imaging, LAL endotoxin testing, and functional binding confirmation.
Target Portfolio
Key Recombinant Extracellular Domain Categories
| Target Class | Representative Targets | Expression Host | Available Formats |
|---|---|---|---|
| Immune Checkpoint Extracellular Domains | PD-1, PD-L1, CTLA-4, LAG-3, TIGIT, TIM-3 | Mammalian (Expi293F) / Insect (Sf9) | Tag-free or His/Fc-tagged |
| Receptor Tyrosine Kinases (RTKs) | EGFR ECD, HER2 ECD, VEGFR-2 ECD, MET ECD | Mammalian (Expi293F) | Monomeric or dimeric Fc-fusions |
| Viral Glycoproteins & Spike Domains | SARS-CoV-2 RBD/Spike, Influenza HA, RSV F protein | Mammalian (Expi293F) / Sf9 | Trimeric prefusion stabilized |
| Cytokine & Chemokine Receptors | IL-6R, IL-4Rα, TNFR1, CCR5 extracellular loops | Mammalian (Expi293F) | High-affinity soluble formats |
| Cell Adhesion & Transport Markers | Transferrin Receptor (TfR1), EpCAM, Claudin loops | Mammalian (Expi293F) | Active binding conformation |
Analytical Standards
Rigorous Quality Control on Every Protein
Multi-Host Expression Screening
Select the ideal production system — Expi293F mammalian cells for human-like glycosylation and complex disulfide patterns, Sf9 insect cells for high eukaryotic yields, or E. coli for rapid non-glycosylated targets.
Multi-Step ÄKTA pure 25 FPLC Purification
Purified using automated capture (Ni-NTA, Strep-Tactin), tag removal (TEV/PreScission cleavage), and analytical-to-preparative size-exclusion polishing (SEC) to guarantee >95% monomeric purity.
Native Folding & Functional Conformation
Engineered construct design with codon optimization, leader sequences for authentic extracellular secretion, and verified receptor-ligand binding kinetics.
Exhaustive Biophysical Characterization
Every protein batch includes SDS-PAGE purity imaging, analytical SEC chromatograms, endotoxin quantification (<1 EU/µg), and concentration measurement by UV absorbance.
Custom ECD Production
Order Recombinant Extracellular Domain Targets
Need a custom extracellular target or high-yield protein batch? Provide your target gene details and our protein engineering team will deliver a comprehensive expression proposal.