| Field | Specification |
|---|---|
| Activity | |
| Alternative Names | GENERATIVE CELL SPECIFIC 1 |
| Conjugate | |
| Endotoxin Level | |
| Expression System | |
| Form | Lyophilized powder |
| Molecular Weight | |
| Product Type | |
| Protein Length | |
| Purity | |
| Reconstitution | |
| Species | |
| Storage | |
| Target | |
| UniProt # |
Overview
This product consists of virus-like particles (VLPs) displaying Arabidopsis thaliana Protein HAPLESS 2 (HAP2)-VLPs derived from Arabidopsis thaliana (Mouse-ear cress). VLP-based presentation can help maintain membrane topology and conformational epitopes for multi-pass proteins, supporting reagent development and binding-focused research. This material is supplied for research use only (RUO).
Key elements and design rationale
- Expressed region: Amino acids 25–705 (681 aa) from the annotated sequence. Region choice can affect folding, solubility, and which epitopes are represented.
- Transmembrane architecture: Annotated as 1TM. Predicted topology influences detergent/lipid dependence, epitope accessibility (extracellular vs cytosolic loops), and how results translate to full-length proteins in membranes.
- Expression system: Mammalian cell. Mammalian expression can support more native-like folding and post-translational modifications for complex membrane proteins, which may be important for conformation-sensitive binding studies.
- Source species: Arabidopsis thaliana (Mouse-ear cress). Ortholog differences can affect epitope conservation and functional interpretation across model systems.
- Reference accession: UniProt F4JP36. Curated annotations and sequence features in public databases can help interpret domains, motifs, and known isoforms.
Membrane proteins can be challenging analytes because conformation and interactions depend on the surrounding membrane environment. When using a recombinant region rather than a native membrane preparation, interpret binding and activity-oriented data in light of the construct boundaries, predicted topology, and expression host.
Biological background
Arabidopsis thaliana Protein HAPLESS 2 (HAP2)-VLPs is a membrane-associated protein from Arabidopsis thaliana. Many membrane proteins participate in transport, signaling, cell–cell interactions, or host–pathogen processes. For less-characterized entries, curated database annotations (e.g., UniProt) and domain predictions provide useful starting points for hypothesis generation. Also reported as: GENERATIVE CELL SPECIFIC 1.
Research relevance and current trends
- Integrating domain prediction, topology mapping, and comparative genomics to refine functional hypotheses for membrane proteins.
- Using structural and biophysical methods (including stabilized constructs and membrane mimetics) to probe conformation and interactions.
- Applying single-cell and spatial omics to understand when and where membrane proteins are expressed and how that links to phenotype.
Common research applications
- Antigen production for antibody generation, epitope mapping, or binder screening against defined regions.
- Biochemical interaction studies (protein–protein or protein–lipid) that inform pathway placement and mechanism.
- Comparative studies of orthologs/variants to explore conserved motifs and potential functional differences.
When interpreting signals from binding or detection assays, changes may reflect altered abundance, localization, or accessibility of the targeted region rather than changes in intrinsic activity. Pairing recombinant-protein results with cellular context (e.g., overexpression/knockdown comparisons or orthogonal readouts) can strengthen conclusions without relying on any single assay format.
Notes for experimental interpretation
- Isoforms, sequence variants, and proteolytic processing can change which extracellular or cytosolic regions are present and therefore which epitopes are detected.
- Post-translational modifications (e.g., glycosylation, disulfide bonding) and the membrane environment can influence conformation and binding; this can differ by expression system and sample type.
- Use appropriate negative/positive control concepts (e.g., knockout/knockdown or overexpression controls, orthogonal antibodies/assays, and matched species/ortholog controls) to support specificity.
VLP display considerations: VLP-based presentation can enrich for native-like membrane topology, but accessibility of specific loops/epitopes can still vary with particle composition and protein orientation. Interpreting binding data benefits from using multiple controls and orthogonal readouts.
What is protein expression and purification?
Why is there no/low protein expression?
b. Rare codons. You should optimize codons, use strains supplementing rare codons, induce at lower temperature or grow in poor media.
c. Protein toxicity. You should use promoters with tighter regulation or lower plasmid copy number. Use pLysS/pLysE bearing strains in T7-based systems or strains that are better for the expression of toxic proteins. Start induction at high OD and shorten induction time. Add glucose when using expression vectors containing lac-based promoters.
How to avoid inclusion bodies and improve soluble expression?
b. Incorrect disulfide bond formation. You should add fusion partners, including thioredoxin, DsbA, DsbC. Clone in a vector containing secretion signal peptide to cell periplasm. Use gamiB (DE3)strains with oxidative cytoplasmic environment. Lower inducer concentration and induction temperature.
c. Incorrect folding. You should use a fusion partner. Co-express with molecular chaperones. Use strains with cold-adapted chaperones. Supplement media with chemical chaperones and cofactors. Reduce the inducer concentration and add fresh media. Induce for a shorter time at low temperature.
Why is the molecular weight of protein smaller than the predicted?
b. Imbalanced translation process of fusion protein. You should change another fusion tag or move fusion tag to C-terminal. You should induce for a shorter time at low temperature or change to poor media.
c. Protein degradation. You should replace specific protease sites. Use protease deficient strains. Induce at high OD. You should induce for a shorter time at low temperature or use protease inhibitors when breaking cells.
Why is the actual band size different from the predicted?
b. Post-translational cleavage. Many proteins are synthesized as pro-proteins, and then cleaved to give the active form.
c. Splice variants. Alternative splicing may create different sized proteins from the same gene.
d. Relative charge. The composition of amino acids have different relative charge which will affect the electrophoretic mobility.
e. Multimers such as dimerisation of a protein. This is usually prevented in reducing conditions, although strong interactions can result in the appearance of higher bands.
f. Protein structure such as disulfide bond, protein secondary structure or protein 3D structure formation.
g. Hydrophobic proteins, such as transmembrane proteins, may have difficulties in migrating into the gel, and thus resulting in different multi-banded patterns.
How to express a protein with bioactivity? Why is the protein inactive?
a. Low solubility of the protein. You should fuse desired protein to a fusion partners and lower temperature.
b. Lack of essential post translational modification. You should change another expression system.
c. Incomplete folding. You should use a fusion partner and use strains with cold-adapted chaperones. Co-express with molecular chaperones at lower temperature. Monitor disulfide bond formation and allow further folding in vitro.
d. Mutations in cDNA. You should sequence plasmid before and after induction or use a recA− strain to ensure plasmid stability. Transform E. coli before each expression round.
Why are our protein products almost invisible in pipes?
Tips: Before opening the lid, we recommend to centrifuge in a small centrifuge for 20-30 seconds firstly to ensure that the contents are on the bottom of the tube. Our quality control steps ensure that the amount of protein contained in each tube is accurate, although sometimes you can’t see the protein powder, but the protein content in the tube is still very accurate.
How is the protein purified? Is the purity guaranteed?
Although we guarantee a minimum purity standard of >85%, some of the proteins we prepared have a purity of 95% or even 97%.
How should I reconstitute and store the products?
As for short-term storage or usage, please use sterile deionized water to completely reconstitute proteins to 0.1-1.0 mg/mL. Aliquot after 10-15 minutes if needed and store at 4℃.
As for long-term storage, the cytokines or recombinant proteins are recommended to add 5-50% of glycerol (final concentration) and aliquot for long-term storage at -20℃/-80℃. Our default final concentration of glycerol is 50%. Customers could use it as reference.
What types of tags do you use for fusion?
What is the impact of a given tag type and any potential biological activity of the protein?
Can you remove the endotoxin?
Can you offer aseptic manufacture processing?
How to determine species cross-reactivity of cytokines?
b. Many mouse cytokines may also have effect on human cells, however, the activity may be lower than the corresponding human cytokines.
c. One of the few human cytokines will be more active than corresponding mouse cytokines when acting on mouse cells, such as IL-7.
d. Interferon, GM-CSF, IL-3 and IL-4 and other cytokines are species-specific and almost have no activity on non-homologous cells.
e. In contrast, fibroblast growth factor (FGF) and neurotrophin are highly conserved and both have good activity on cells of different species.
What is the general preservative? Which kind of preservative do you usually add?
What is the general protectant? What kind of protectant do you usually add?
Can’t Find What You’re Looking For? We can help you source the best match or customize a recombinant protein solution for your study. Options may include species (human/mouse/rat), protein region/domain (full-length vs fragment), tag or label (His/GST/FLAG/biotin/fluorescent), expression system (E. coli/HEK293/insect), purity grade, formulation (buffer, carrier-free, glycerol-free), activity/functional validation (binding or enzymatic assays), endotoxin level (low-endotoxin for cell-based work), mutants/variants (point mutations, isoforms), and bulk or custom packaging. Click Talk to a Scientist to submit a request form, email us at support@biohippo.com, or explore our Research Services for additional support. Our team will be in contact with you shortly.
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