Recombinant Human Olfactory receptor 8D2 (OR8D2)
Description
Introduction to Olfactory Receptor 8D2 (OR8D2)
Olfactory Receptor 8D2, commonly abbreviated as OR8D2, is a protein encoded by the OR8D2 gene in humans. Also known as JCG2, this receptor belongs to the olfactory receptor family 8, subfamily D, member 2 . Olfactory receptors like OR8D2 play a crucial role in our ability to detect and process odorant molecules, initiating neuronal responses that ultimately lead to smell perception . As part of the largest gene family in the human genome, OR8D2 represents one of approximately 400 intact human odorant receptors, though only about 10% of these receptors have published ligand data .
OR8D2 belongs to the superfamily of G-protein-coupled receptors (GPCRs), which are characterized by their seven transmembrane domain structure. This structural arrangement is common among many neurotransmitter and hormone receptors and facilitates the recognition and G protein-mediated transduction of odorant signals . The nomenclature assigned to olfactory receptor genes and proteins, including OR8D2, is species-specific and independent of naming conventions used for other organisms .
Molecular Structure
As a G-protein-coupled receptor, OR8D2 features the characteristic seven-transmembrane domain architecture that enables it to interact with extracellular odorant molecules and intracellular signaling pathways . This structural arrangement allows the receptor to undergo conformational changes upon binding with specific odorants, triggering downstream signaling cascades that ultimately result in smell perception.
The human OR8D2 gene encodes a protein with a theoretical molecular weight of approximately 61.3 kDa . Like other olfactory receptors, OR8D2 arises from a single coding-exon gene, which is a distinctive feature of this receptor family . The correct conformational folding of OR8D2 is essential for its biological function, as it directly impacts the receptor's ability to recognize and bind specific odorant molecules.
Functional Role
OR8D2, like other olfactory receptors, interacts with odorant molecules in the nasal cavity, initiating a neuronal response cascade that ultimately leads to smell perception . The primary function of OR8D2 involves:
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Recognition of specific odorant molecules
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G protein-mediated transduction of odorant signals
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Initiation of neuronal responses leading to smell perception
Research indicates that OR8D2 has 904 functional associations with biological entities spanning 8 different categories, including molecular profiles, organisms, functional terms, phrases or references, diseases, phenotypes or traits, chemicals, structural features, cell lines, cell types or tissues, genes, proteins, and microRNAs . These associations have been extracted from 49 distinct datasets, highlighting the complex role of OR8D2 in various biological processes.
Expression Systems
Recombinant human OR8D2 can be produced using various expression systems, each with specific advantages for research applications. One commercially available form is the Recombinant Human OR8D2 GST (N-Term) protein, which is produced using an in vitro wheat germ expression system . This system is particularly valuable for producing OR8D2 as it helps preserve the correct conformational folding necessary for biological function .
The wheat germ expression system offers several advantages for the production of recombinant OR8D2:
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Maintains appropriate protein folding
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Produces functional protein with native-like characteristics
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Avoids potential issues with toxicity that might occur in cellular expression systems
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Allows for controlled production conditions
Another approach involves the production of OR8D2 in synthetic nanodiscs, which provide a more native-like membrane environment for this transmembrane receptor . This method may enhance the stability and functionality of the recombinant protein by mimicking its natural lipid bilayer environment.
Purification and Quality Control
After expression, recombinant OR8D2 undergoes purification processes to ensure high quality and purity. For the GST-tagged recombinant OR8D2, purification typically involves affinity chromatography leveraging the GST tag. The resulting purified protein demonstrates a purity of greater than 80% as assessed by SDS-PAGE and Coomassie blue staining .
Quality control measures for recombinant OR8D2 include:
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SDS-PAGE analysis to confirm molecular weight and purity
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Western blot verification of identity
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Functional assays (when applicable)
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Testing for endotoxin and other contaminants
It's important to note that while the recombinant OR8D2 protein produced in wheat germ expression systems should theoretically preserve correct conformational folding, the functionality of commercially available recombinant OR8D2 has not been explicitly measured or validated in all cases .
Physical and Chemical Properties
Table 1: Physical and Chemical Properties of Recombinant Human OR8D2
Experimental Applications
Recombinant human OR8D2 finds utility in various research applications aimed at understanding olfactory receptor function and odorant binding mechanisms. Common applications include:
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Western Blot analysis for protein detection and characterization
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ELISA assays for quantitative measurement
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Protein array studies for interaction mapping
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Immunoaffinity purification of interacting partners
These applications contribute to our understanding of OR8D2's role in olfactory perception and potentially in other physiological processes.
Detection Methods
Dedicated detection tools for OR8D2 have been developed, including ELISA kits specifically designed for quantitative measurement of OR8D2 in various sample types. These kits typically employ a competition ELISA method and offer:
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Detection range: 250-5000 pg/mL
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Minimum detection limit: 250 pg/mL
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Sensitivity: 1.0 pg/mL
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Compatibility with various sample types including cell culture supernatant, plasma, serum, and tissue homogenates
For functional studies, heterologous luciferase assays have been employed to screen odorants against olfactory receptors including OR8D2 . This approach allows researchers to identify potential ligands and characterize receptor-odorant interactions in a controlled experimental setting.
Receptor-Ligand Interactions
Despite the importance of olfactory receptors in odor perception, our understanding of the specific chemical features encoded by these receptors remains limited. This knowledge gap is largely due to the vast search space covering interactions between hundreds of receptors and billions of odorous molecules . Research efforts involving OR8D2 contribute to addressing this challenge by characterizing specific receptor-ligand interactions.
Biological Associations
Analysis of OR8D2's biological associations reveals its potential involvement in various physiological processes beyond olfaction. OR8D2 exhibits functional associations with biological entities spanning multiple categories:
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Molecular profiles
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Organisms
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Functional terms
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Phrases or references
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Diseases
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Phenotypes or traits
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Chemicals
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Structural features
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Cell lines, cell types, or tissues
These diverse associations suggest that OR8D2 may have broader physiological roles than previously recognized, potentially contributing to processes outside the olfactory system.
Expanding Functional Characterization
Future research on recombinant human OR8D2 should focus on comprehensive functional characterization to validate its biological activity and identify specific ligands. While current recombinant proteins preserve conformational folding necessary for function, explicit measurement and validation of OR8D2's functionality would significantly advance our understanding of this receptor .
Developing improved expression systems and purification methods could enhance the quality and yield of recombinant OR8D2, facilitating more extensive functional studies. Additionally, incorporating OR8D2 into lipid nanodiscs or other membrane-mimetic environments may provide more physiologically relevant conditions for studying this transmembrane receptor .
Applications in Olfactory Research
Recombinant OR8D2 has significant potential for advancing our understanding of human olfaction. By characterizing OR8D2's ligand binding profile and signaling properties, researchers can contribute to elucidating the combinatorial code underlying odor perception. This knowledge could inform applications in various fields:
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Development of artificial sensors based on olfactory receptor principles
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Design of novel fragrances and flavors with specific receptor-targeting properties
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Understanding olfactory disorders and potential therapeutic approaches
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Exploration of evolutionary relationships between olfactory receptors across species
Product Specs
Note: While we prioritize shipping the format currently in stock, please specify your format preference during order placement for customized preparation.
Note: All proteins are shipped with standard blue ice packs. Dry ice shipping requires prior arrangement and incurs additional charges.
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Target Background
Q&A
What is Recombinant Human Olfactory Receptor 8D2 and its functional significance?
Recombinant Human Olfactory Receptor 8D2 (OR8D2), also known as Olfactory receptor OR11-303 or Olfactory receptor-like protein JCG2, is a full-length (311 amino acids) G-protein coupled receptor that belongs to the olfactory receptor family . OR8D2 participates in G-protein coupled receptor signaling pathways critical for olfactory sensation . Recent studies have identified OR8D2 as a differentially expressed gene between myocardial infarction patients and healthy individuals, suggesting its potential role beyond olfactory function . Methodologically, researchers should approach OR8D2 as a multifunctional receptor with diverse signaling capabilities rather than limiting investigations to olfactory contexts.
How should researchers handle expression and purification of Recombinant OR8D2?
For optimal expression, recombinant OR8D2 can be produced in E. coli expression systems with an N-terminal His-tag to facilitate purification . To enhance cell surface expression in heterologous systems, researchers should consider adding a signal peptide (such as Rho-tag) to the N-terminus and co-expressing OR chaperones like RTPs (RTP1, RTP1S, RTP2) and REEP1, along with G-protein chaperone Ric-8B . This methodological approach significantly improves the functional expression of olfactory receptors on cell membranes, facilitating binding assays and functional studies.
What are recommended storage and reconstitution protocols for Recombinant OR8D2?
The optimal storage conditions for recombinant OR8D2 are:
| Storage Phase | Recommended Conditions | Notes |
|---|---|---|
| Long-term | -20°C/-80°C | Aliquoting necessary for multiple use |
| Working | 4°C | Up to one week |
| Buffer | Tris/PBS-based, 6% Trehalose, pH 8.0 | Maintains protein stability |
For reconstitution, briefly centrifuge the vial prior to opening and reconstitute the protein in deionized sterile water to a concentration of 0.1-1.0 mg/mL . Addition of 5-50% glycerol (final concentration) is recommended for aliquoting and long-term storage, with 50% being the default glycerol concentration . Repeated freeze-thaw cycles should be avoided to maintain protein integrity.
What experimental designs are optimal for OR8D2 functional characterization?
When designing functional studies for OR8D2, researchers should implement comprehensive approaches that capture both binding affinity and downstream signaling cascades. Since OR8D2, like other olfactory receptors, couples to G-proteins that activate adenylate cyclase to produce cAMP, assaying cAMP production provides an effective measure of receptor activation .
Beyond endpoint measurements, real-time analysis using fluorescent calcium indicators (like GCaMP) or cyclic nucleotide-gated channels (CNGs) co-expressed with OR8D2 allows for dynamic assessment of receptor responses . This methodological approach enables researchers to detect subtle temporal variations in signaling that might be missed with traditional endpoint measurements.
How can researchers optimize heterologous expression systems for OR8D2 studies?
For maximizing functional OR8D2 expression in heterologous systems, researchers should implement the following protocol:
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Select an appropriate cell line such as HEK293T that allows for high transfection efficiency and proper protein processing
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Modify the OR8D2 construct with a signal peptide (e.g., Rho-tag) at the N-terminus
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Co-express specialized OR chaperones (RTPs and REEP1)
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Include the G-protein chaperone Ric-8B to enhance coupling
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Stably express signaling detection systems such as CNGs or Ca²⁺-dependent fluorescent proteins (GCaMP)
This comprehensive approach overcomes the historically poor cell surface expression of olfactory receptors in heterologous systems, allowing for more reliable functional studies.
What signaling pathways are associated with OR8D2 and how should they be investigated?
OR8D2 participates in G-protein coupled receptor signaling pathways, specifically through G-protein αolf/αs-linked mechanisms that increase intracellular cAMP levels . The canonical signaling cascade involves:
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Odorant binding to OR8D2
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Activation of G-proteins
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Stimulation of adenylate cyclase
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Production of cAMP
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Activation of protein kinase A (PKA)
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Phosphorylation of cAMP response element binding (CREB) protein
To properly investigate these pathways, researchers should employ luciferase assays analyzing CREB-induced gene transcription downstream of OR8D2 activation . This methodology allows for quantitative assessment of receptor function through the entire signaling cascade rather than just ligand binding.
What is the emerging role of OR8D2 in cardiovascular pathology?
Recent studies have identified OR8D2 as a differentially expressed gene between myocardial infarction (MI) patients and healthy individuals, suggesting its potential as a biomarker for MI prediction . Functional enrichment analysis has shown that OR8D2 is associated with G-protein coupled receptor signaling, which may link it to cardiovascular pathophysiology .
When investigating OR8D2's role in cardiovascular contexts, researchers should:
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Assess OR8D2 expression levels in relevant tissues and circulation
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Correlate expression patterns with clinical parameters
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Perform functional validation studies to determine causality
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Consider potential interactions with other biomarkers
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Account for confounding factors such as prior treatment with medications like nitroglycerin
Future research directions should include validation in larger patient cohorts and potential combination with other diagnostic methodologies for improved clinical utility.
What methods are available for real-time measurement of OR8D2 activity?
To overcome limitations of endpoint measurements in OR8D2 research, several real-time measurement techniques can be implemented:
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Co-expression of OR8D2 with cyclic nucleotide-gated channels (CNGs) to detect cAMP-mediated responses through calcium influx
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Integration of genetically encoded calcium indicators like GCaMP for fluorescence-based detection
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Establishment of microwell systems for high-throughput screening
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Implementation of automated dispensing robots for precise stimulation protocols
These methodological approaches allow researchers to detect the dynamic and often transient responses of OR8D2 to ligands, providing more comprehensive functional data than traditional endpoint assays.
How can researchers address data contradictions in OR8D2 signaling studies?
When confronting contradictory findings in OR8D2 research, investigators should systematically evaluate:
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Expression system variations (E. coli vs. mammalian cells)
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Presence or absence of chaperone proteins
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Tag positions and their potential interference with function
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Reagent quality and experimental conditions
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Temporal dimensions of measurements (endpoint vs. real-time)
Methodologically, researchers should implement multiple complementary assays to validate findings and carefully document all experimental conditions to facilitate reproducibility. Cross-validation between different expression systems and measurement techniques provides the most reliable characterization of OR8D2 signaling properties.
What theoretical frameworks should guide OR8D2 research in multidisciplinary contexts?
When designing research on OR8D2 that spans multiple disciplines (e.g., molecular biology, biochemistry, and clinical medicine), researchers should adopt comprehensive theoretical frameworks such as the PRECEDE-PROCEED model4. This approach enables structured analysis that links basic molecular mechanisms to broader physiological and clinical outcomes.
The framework helps researchers:
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Define clear research questions with measurable outcomes
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Establish causal relationships between molecular interactions and physiological effects
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Account for environmental, behavioral, and genetic factors
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Develop intervention strategies based on mechanistic understanding
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Evaluate outcomes systematically4
By applying such frameworks, researchers can conduct more integrated studies that connect OR8D2's molecular properties to its potential roles in complex physiological and pathological processes.
