GNB5 Protein: Biological Background and Significance

GNB5 (G Protein Subunit Beta 5) is a member of the WD40 repeat protein superfamily and constitutes an atypical beta subunit of heterotrimeric G proteins. Unlike conventional Gβ subunits (GNB1–GNB4), GNB5 preferentially associates with the R7 family of regulator of G-protein signaling (RGS) proteins—including RGS6, RGS7, RGS9, and RGS11—rather than forming the canonical Gβγ dimer with Gγ subunits. This unique partnership regulates the deactivation kinetics of Gαi/o-coupled receptors, placing GNB5 at the center of visual signal transduction, neuronal signaling, and cardiac rhythm modulation.

Loss-of-function variants in the GNB5 gene have been associated with severe intellectual disability, cardiac arrhythmias (including sick sinus syndrome), and visual impairment in humans, underscoring its physiological importance. Recombinant Human GNB5 Protein therefore provides a valuable biochemical tool for dissecting these pathways in vitro.

Product Specifications and Quality Attributes

Aladdin Scientific's Recombinant Human GNB5 Protein (SKU: rp370331) is produced using recombinant expression technology to deliver a well-characterized, research-grade protein suitable for a range of biochemical and cell-based assays. Key quality attributes researchers should consider include:

• Purity: Recombinant proteins of this class are typically assessed by SDS-PAGE and/or HPLC to confirm purity levels appropriate for functional studies. Please consult the current Certificate of Analysis (CoA) for lot-specific purity data.
• Biological Activity: Functional validation may include binding assays with known GNB5 interaction partners such as RGS7 or RGS9. Refer to the product datasheet for validated activity data.
• Formulation: Specific buffer composition, concentration, and carrier protein information are provided on the product datasheet and CoA for each lot.
• Endotoxin Level: Endotoxin content should be verified on the CoA for applications sensitive to LPS contamination.

Note: Specific numerical values for purity, concentration, and endotoxin are lot-dependent. Always consult the supplied CoA before use.

Recommended Handling and Storage Protocol

Proper handling and storage of Recombinant Human GNB5 Protein are essential to preserve biological activity and ensure reproducible experimental results. Follow these guidelines:

1. Upon Receipt: Inspect the package immediately. If the product has been shipped on dry ice, allow it to equilibrate briefly at the recommended storage temperature before opening.
2. Reconstitution: If supplied lyophilized, reconstitute in the buffer specified on the datasheet. Allow the vial to equilibrate to room temperature, add the appropriate volume of sterile, ultrapure water or the recommended buffer, and gently mix. Avoid vortexing.
3. Aliquoting: Prepare single-use aliquots immediately after reconstitution to minimize freeze-thaw cycles, which can lead to protein aggregation and loss of activity.
4. Short-term Storage: For use within 1–2 weeks, store aliquots at 4 °C. Add a carrier protein such as 0.1% BSA if diluting to low concentrations to prevent adsorptive losses.
5. Long-term Storage: Store at -80 °C. Avoid storing at -20 °C due to potential ice-crystal formation in frost-free freezers.
6. Thawing: Thaw on ice; do not use a water bath or heat block above 37 °C. Mix gently after thawing and centrifuge briefly before use.

Always consult the product-specific datasheet for formulation-dependent storage instructions that supersede general guidance.

Research Applications of Recombinant Human GNB5 Protein

Recombinant Human GNB5 Protein is a versatile reagent applicable across multiple research disciplines. Representative applications include:

• Protein–Protein Interaction Studies: GNB5 serves as a bait or prey protein in pull-down assays, co-immunoprecipitation experiments, and surface plasmon resonance (SPR) studies to characterize its interactions with RGS proteins and other binding partners.
• Structural Biology: Purified recombinant GNB5 can be used in crystallography or cryo-EM sample preparation to elucidate the three-dimensional architecture of GNB5–RGS complexes.
• Enzyme and GTPase Activity Assays: GNB5-containing complexes modulate GTPase-accelerating activity of RGS proteins toward Gα subunits; recombinant GNB5 enables reconstitution of these regulatory complexes in vitro for kinetic analysis.
• Antibody Validation: Recombinant GNB5 protein can serve as a positive control antigen for validating anti-GNB5 antibodies used in Western blot, ELISA, or immunofluorescence.
• Drug Discovery and Screening: As a component of the RGS–Gβ5 signaling axis, recombinant GNB5 supports the development of biochemical assays to identify small-molecule modulators of G-protein signaling pathways.
• Disease Mechanism Research: Enables in vitro modeling of GNB5-associated disorders including intellectual disability and cardiac arrhythmia by assessing the impact of disease-associated mutations on protein function.

Ordering, Quality Assurance, and Technical Support

Recombinant Human GNB5 Protein (SKU: rp370331) is available through Aladdin Scientific. To ensure you receive the correct product and documentation:

• Ordering: Reference SKU rp370331 when placing your order online or through your Aladdin Scientific account representative. Bulk and custom quantities may be available upon request.
• Certificate of Analysis (CoA): A lot-specific CoA is provided with each shipment and is accessible online by lot number. Review purity, activity, and endotoxin data before experimental use.
• Quality Assurance: All Aladdin Scientific recombinant proteins undergo internal quality control testing prior to release. Specific QC methods and acceptance criteria are detailed in the product datasheet.
• Technical Support: For questions regarding reconstitution, optimal assay conditions, or troubleshooting, contact Aladdin Scientific's technical support team. Provide the SKU and lot number for faster assistance.
• Returns and Refunds: Refer to Aladdin Scientific's standard returns and refunds policy if the product arrives damaged or does not meet specifications as stated on the CoA.