HBV-X, His Tag

The Hepatitis B virus X protein (HBx), with a molecular weight of 17 kDa, functions as a transcriptional coactivator and plays a crucial role in regulating genes associated with inflammation and cell survival. It exerts its regulatory effects on various transcription factors, including NF-kappaB, and is heavily implicated in the development of liver cancer (hepatocarcinogenesis). Notably, HBx facilitates the binding of cAMP response element binding protein (CREB) to its corresponding response element. Furthermore, HBx stabilizes the cellular coactivator ASC-2 via direct protein-protein interaction, thereby influencing the regulation of genes actively transcribed in liver cancer cells. It also activates both the JNK and MAPK signaling pathways, contributing to the mobilization of cytosolic Ca2+. The interaction between HBx and the general transcription factor TFIIB represents another mechanism underlying its transcriptional transactivation activity. Importantly, HBx has been shown to downregulate the expression of PTEN, a known tumor suppressor gene and a negative regulator of the phosphatidylinositol 3'-kinase/AKT pathway. The development of hepatocellular carcinoma (HCC) is often linked to hepatitis B virus (HBV) infection, and HBx, in particular, plays a pivotal role in HBV-related HCC. The persistent presence of HBx is critical to the pathogenesis of early-stage HCC, and its expression in the liver during chronic HBV infection may serve as a valuable prognostic marker for HCC development.

Recombinant HBV-X, produced in E. coli, is a single polypeptide chain comprising 165 amino acids (residues 2-154) with a molecular weight of 17.8 kDa. It is fused to a 12 amino acid His-tag at the N-terminus and purified using proprietary chromatographic techniques.

Exceeds 90%.

The protein is filtered through a 0.4 μm filter and subsequently lyophilized from a solution containing 0.5 mg/ml protein in 50 mM acetate buffer (pH 4) and 5% trehalose.

To prepare a working stock solution of approximately 0.5 mg/ml, it is recommended to reconstitute the lyophilized protein by adding 0.1 M acetate buffer (pH 4) and ensure complete dissolution. For conversion to a higher pH value, it is advisable to dilute the solution extensively with the appropriate buffer to a concentration of 10 μg/ml. It's important to note that the solubility of HBV X antigen is limited at higher concentrations. Before using this non-sterile product in cell culture, it is essential to filter sterilize your culture media or working solutions containing it.

For long-term storage, the lyophilized protein should be kept at -20°C. After reconstitution, it is recommended to aliquot the product to minimize repeated freeze-thaw cycles. The reconstituted protein remains stable at 4°C for a limited period; no significant changes have been observed after two weeks of storage at 4°C.

Escherichia Coli.

MRGSHHHHHH GSAARVCCQL DPARDVLCLR PVGAESRGRP VSGPFGTLPS PSSSAVPADH GAHLSLRGLP VCAFSSAGPC ALRFTSARRM ETTVNAHQVL PKVLHKRTLG LSAMSTTDLE AYFKDCLFKD WEELGEEIRL KVFVLGGCRH KLVCSPAPCN FFTSA.