| Field | Specification |
|---|---|
| Mfr No | |
| Activity | |
| Alternative Names | HLA class I histocompatibility antigen; B alpha chain (HLA-B); partial; (Human leukocyte antigen B)(HLA-B) |
| Conjugate | |
| Endotoxin Level | |
| Expression System | |
| Form | Liquid or Lyophilized powder |
| Molecular Weight | |
| Product Type | |
| Protein Length | |
| Purity | |
| Reconstitution | |
| Species | |
| Storage | |
| Target | |
| UniProt # |
Overview
Recombinant Human HLA class I histocompatibility antigen,B alpha chain (HLA-B), partial is a recombinant protein reagent derived from Homo sapiens (Human) and produced in E.coli. It is commonly used to support Others research by enabling antigen presentation and binding assays, immune receptor interaction studies and structural immunology in controlled in vitro settings.
Key elements and design rationale
- Expressed region: 25-309aa. Region selection can focus on functional domains, improve solubility, or isolate interaction surfaces for targeted studies.
- Expression system: E.coli. Expression host can influence folding and the presence/absence of post-translational modifications.
- Tag / fusion: N-terminal 6xHis-tagged. Tags can support purification and detection; evaluate potential tag effects when studying sensitive interactions.
- Molecular weight (reported): 38.9 kDa. Apparent size may vary with tags, processing, and gel conditions.
When comparing results across batches or platforms, interpret signals in the context of construct design (region, tags) and expression host, especially for modification-dependent interactions.
Biological background
The gene commonly associated with this target is HLA-B. HLA-B refers to a protein target that is studied across multiple biological contexts; annotations and nomenclature can vary by species and isoform. This product corresponds to the Homo sapiens (Human) sequence context, which can be important when comparing homologs or orthologs across model systems. For curated functional annotations, domains, and sequence features, consult primary databases (e.g., UniProt/NCBI) and the recent literature for the specific organism and isoform.
Research relevance and current trends
- Using recombinant proteins to enable quantitative binding measurements and reagent benchmarking.
- Studying domain- and isoform-specific effects in pathway models and interaction networks.
- Developing robust, reproducible assays that connect molecular readouts to cellular phenotypes.
Relevance: Antigen-presenting major histocompatibility complex class I (MHCI) molecule. In complex with B2M/beta 2 microglobulin displays primarily viral and tumor-derived peptides on antigen-presenting cells for recognition by alpha-beta T cell receptor (TCR) on HLA-B-restricted CD8-positive T cells, guiding antigen-specific T cell immune response to eliminate infected or transformed cells. May also present self-peptides derived from the signal sequence of secreted or membrane proteins, although T cells specific for these peptides are usually inactivated to prevent autoreactivity. Both the peptide and the MHC molecule are recognized by TCR, the peptide is responsible for the fine specificity of antigen recognition and MHC residues account for the MHC restriction of T cells. Typically presents intracellular peptide antigens of 8 to 13 amino acids that arise from cytosolic proteolysis via constitutive proteasome and IFNG-induced immunoproteasome. Can bind different peptides containing allele-specific binding motifs, which are mainly defined by anchor residues at position 2 and 9. ; Allele B*07:02: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and mainly a Leu anchor residue at the C-terminus. Presents a long peptide (APRGPHGGAASGL) derived from the cancer-testis antigen CTAG1A/NY-ESO-1, eliciting a polyclonal CD8-positive T cell response against tumor cells. Presents viral epitopes derived from HIV-1 gag-pol (TPQDLNTML) and Nef (RPQVPLRPM). Presents an immunodominant epitope derived from SARS-CoV-2 N/nucleoprotein (SPRWYFYYL). Displays self-peptides including a peptide derived from the signal sequence of HLA-DPB1 (APRTVALTA). ; Allele B*08:01: Presents to CD8-positive T cells viral epitopes derived from EBV/HHV-4 EBNA3 (QAKWRLQTL), eliciting cytotoxic T cell response. ; Allele B*13:02: Presents multiple HIV-1 epitopes derived from gag (RQANFLGKI, GQMREPRGSDI), nef (RQDILDLWI), gag-pol (RQYDQILIE, GQGQWTYQI) and rev (LQLPPLERL), all having in common a Gln residue at position 2 and mainly hydrophobic amino acids Leu, Ile or Val at the C-terminus. Associated with succesful control of HIV-1 infection. ; Allele B*18:01: Preferentially presents octomeric and nonameric peptides sharing a common motif, namely a Glu at position 2 and Phe or Tyr anchor residues at the C-terminus. Presents an EBV/HHV-4 epitope derived from BZLF1 (SELEIKRY). May present to CD8-positive T cells an antigenic peptide derived from MAGEA3 (MEVDPIGHLY), triggering an anti-tumor immune response. May display a broad repertoire of self-peptides with a preference for peptides derived from RNA-binding proteins. ; Allele B*27:05: Presents to CD8-positive T cells immunodominant viral epitopes derived from HCV POLG (ARMILMTHF), HIV-1 gag (KRWIILGLNK), IAV NP (SRYWAIRTR), SARS-CoV-2 N/nucleoprotein (QRNAPRITF), EBV/HHV-4 EBNA4 (HRCQAIRKK) and EBV/HHV-4 EBNA6 (RRIYDLIEL), confering longterm protection against viral infection. Can present self-peptides derived from cytosolic and nuclear proteins. All peptides carry an Arg at position 2. The peptide-bound form interacts with NK cell inhibitory receptor KIR3DL1 and inhibits NK cell activation in a peptide-specific way, being particularly sensitive to the nature of the amino acid side chain at position 8 of the antigenic peptide. KIR3DL1 fails to recognize HLA-B*27:05 in complex with B2M and EBV/HHV-4 EBNA6 (RRIYDLIEL) peptide, which can lead to increased activation of NK cells during infection. May present an altered repertoire of peptides in the absence of TAP1-TAP2 and TAPBPL. ; Allele B*40:01: Presents immunodominant viral epitopes derived from EBV/HHV-4 LMP2 (IEDPPFNSL) and SARS-CoV-2 N/nucleoprotein (MEVTPSGTWL), triggering memory CD8-positive T cell response. Displays self-peptides sharing a signature motif, namely a Glu at position 2 and a Leu anchor residue at the C-terminus. ; Allele B*41:01: Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Ala or Pro anchor residues at the C-terminus. ; Allele B*44:02: Presents immunodominant viral epitopes derived from EBV/HHV-4 EBNA4 (VEITPYKPTW) and EBNA6 (AEGGVGWRHW, EENLLDFVRF), triggering memory CD8-positive T cell response. Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Phe, Tyr or Trp anchor residues at the C-terminus. ; Allele B*45:01: Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Ala or Pro anchor residues at the C-terminus. ; Allele B*46:01: Preferentially presents nonameric peptides sharing a signature motif, namely Ala and Leu at position 2 and Tyr, Phe, Leu, or Met anchor residues at the C-terminus. The peptide-bound form interacts with KIR2DL3 and inhibits NK cell cytotoxic response in a peptide-specific way. ; Allele B*47:01: Displays self-peptides sharing a signature motif, namely an Asp at position 2 and Leu or Met anchor residues at the C-terminus. ; Allele B*49:01: Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Ile or Val anchor residues at the C-terminus. ; Allele B*50:01: Displays self-peptides sharing a signature motif, namely a Glu at position 2 and Ala or Pro anchor residues at the C-terminus. ; Allele B*51:01: Presents an octomeric HIV-1 epitope derived from gag-pol (TAFTIPSI) to the public TRAV17/TRBV7-3 TCR clonotype, strongly suppressing HIV-1 replication. ; Allele B*54:01: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and Ala anchor residue at the C-terminus. ; Allele B*55:01: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and Ala anchor residue at the C-terminus. ; Allele B*56:01: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and Ala anchor residue at the C-terminus. ; Allele B*57:01: The peptide-bound form recognizes KIR3DL1 and inhibits NK cell cytotoxic response. ; Allele B*67:01: Displays peptides sharing a common signature motif, namely a Pro residue at position 2 and Leu anchor residue at the C-terminus.
Common research applications
- Assay and standard development for immunoassays or binding-based detection methods.
- Protein–protein interaction studies (e.g., receptor–ligand or complex assembly) using purified components.
- Structure–function analysis, including domain mapping or evaluation of sequence variants.
In quantitative assay development, changes in binding or activity readouts are typically interpreted relative to appropriate negative/positive controls and, where possible, orthogonal assay formats that support the same conclusion.
Notes for experimental interpretation
- Recombinant constructs may represent a defined region (domain) rather than the full-length protein; interpret results in the context of the expressed region.
- Tag or fusion elements can aid purification and detection but may influence binding surfaces or oligomerization; consider tag controls when relevant.
- Species and isoform differences can affect interaction partners and post-translational modifications; align experimental controls to the intended biological context.
- E. coli expression can limit eukaryotic post-translational modifications; for modification-dependent biology, interpret results accordingly.
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.
