{"product_id":"recombinant-woodchuck-hepatitis-b-virus-protein-x-x-bhp10516042","title":"Recombinant Woodchuck hepatitis B virus Protein X (X)","description":"\u003ch2\u003eOverview\u003c\/h2\u003e\u003cp\u003eRecombinant Woodchuck hepatitis B virus Protein X (X) is a recombinant protein preparation derived from Woodchuck hepatitis B virus (isolate 8) (WHV). It is commonly used as a defined reagent for assay development, binding studies, and analytical controls where consistent protein specifications are required.\u003c\/p\u003e\u003ch2\u003eKey elements and design rationale\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExpressed region:\u003c\/strong\u003e 1-141aa.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExpression system:\u003c\/strong\u003e E.coli (may influence folding and post-translational modifications).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTag\/format:\u003c\/strong\u003e C-terminal 6xHis-tagged; Liquid or Lyophilized powder.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExpected size:\u003c\/strong\u003e 21.3 kDa (as provided).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePurity:\u003c\/strong\u003e Greater than 85% as determined by SDS-PAGE.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eRegion choice, expression system, and tag\/format can influence folding, post-translational modifications, and interaction behavior in downstream assays.\u003c\/p\u003e\u003ch2\u003eBiological background\u003c\/h2\u003e\u003cp\u003eMultifunctional protein that plays a role in silencing host antiviral defenses and promoting viral transcription. Does not seem to be essential for HBV infection. May be directly involved in development of cirrhosis and liver cancer (hepatocellular carcinoma). Most of cytosolic activities involve modulation of cytosolic calcium. The effect on apoptosis is controversial depending on the cell types in which the studies have been conducted. May induce apoptosis by localizing in mitochondria and causing loss of mitochondrial membrane potential. May also modulate apoptosis by binding host CFLAR, a key regulator of the death-inducing signaling complex (DISC). Promotes viral transcription by using the host E3 ubiquitin ligase DDB1 to target the SMC5-SMC6 complex to proteasomal degradation. This host complex would otherwise bind to viral episomal DNA, and prevents its transcription. Moderately stimulates transcription of many different viral and cellular transcription elements. Promoters and enhancers stimulated by HBx contain DNA binding sites for NF-kappa-B, AP-1, AP-2, c-EBP, ATF\/CREB, or the calcium-activated factor NF-AT\u003c\/p\u003e\u003ch2\u003eResearch relevance and current trends\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eAntigen design and domain selection to better capture neutralizing versus non-neutralizing antibody responses.\u003c\/li\u003e\n\u003cli\u003eHigh-throughput serology and antibody screening using standardized antigens and plate-based formats.\u003c\/li\u003e\n\u003cli\u003eIntegrating binding kinetics with epitope mapping to support variant-aware immunology studies.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCommon research applications\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eCoat plates with WHV-X antigen for ELISA antibody titration (serum\/plasma).\u003c\/li\u003e\n\u003cli\u003eScreen anti-WHV-X antibodies by indirect ELISA and immunoblot readouts.\u003c\/li\u003e\n\u003cli\u003eMap antigenic epitopes using WHV-X fragments\/domains (in vitro binding assays).\u003c\/li\u003e\n\u003cli\u003eDevelop antigen-capture assays using WHV-X as a standard (spike-in controls).\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eInterpret results in the context of the biological system, assay format, and any known domain\/isoform constraints for the target.\u003c\/p\u003e\u003ch2\u003eNotes for experimental interpretation\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eAntigenic proteins may contain immunodominant regions; domain choice can affect assay readouts and cross-reactivity.\u003c\/li\u003e\n\u003cli\u003eInclude relevant negative controls (e.g., unrelated antigens) and dilution series to support interpretation of binding signals.\u003c\/li\u003e\n\u003c\/ul\u003e\u003c!-- Sources (internal): - UniProtKB entry (P17401) — UniProt: https:\/\/www.uniprot.org\/uniprotkb\/P17401 - NCBI Gene search (X) — NCBI: https:\/\/www.ncbi.nlm.nih.gov\/gene\/?term=X - PubMed search — NLM: https:\/\/pubmed.ncbi.nlm.nih.gov\/?term=WHV-X - Reactome pathway browser — Reactome: https:\/\/reactome.org\/ - InterPro protein family resource — EMBL-EBI: https:\/\/www.ebi.ac.uk\/interpro\/ --\u003e","brand":"CUSABIO TECHNOLOGY LLC","offers":[{"title":"1 mg","offer_id":53059304980845,"sku":"CSB-EP323774WAWc7-1MG","price":2466.0,"currency_code":"USD","in_stock":true},{"title":"100 ug","offer_id":53059454370157,"sku":"CSB-EP323774WAWc7-100UG","price":729.0,"currency_code":"USD","in_stock":true},{"title":"20 ug","offer_id":53059454402925,"sku":"CSB-EP323774WAWc7-20UG","price":388.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0949\/7424\/7277\/files\/CSB-EP323774WAWc7-SDS.jpg?v=1772280363","url":"https:\/\/www.ebiohippo.com\/products\/recombinant-woodchuck-hepatitis-b-virus-protein-x-x-bhp10516042","provider":"BioHippo","version":"1.0","type":"link"}