Aims: IP3 is a key regulator molecule in the message transmission pathway, and releases calcium into the cytoplasm by binding intracellular IP3R receptors on the surface of the internal calcium stores. The aim of this study was expression, purification, and characterization of IP3-binding domain from human type 2.
Materials and Methods: In this experimental study, the pET-28a plasmid of the carrier of the IP3BD gene was transferred to the E.coli expression strain BL21 (DE3) by chemical method. In order to optimize the expression in the bacterial system, the expression was studied in different conditions, and various temperatures such as 16, 18, 20, and 24°C, the different times after incubation, type of inducer, and its different concentrations were investigated. The induced bacteria were purified on the basis of thermal shock through nickel column for chromatography and the purity of the protein was measured through SDS-PAGE. The fluorescence emission of IP3-binding domain was measured in the presence and absence of an IP3 ligand at wavelength of 295nm.
Findings: Protein did not have a significant expression in LB, TB, and 2xYT environments, and no changes were observed at different times. Expression of bacterial protein at 20°C based on thermal shock of 42°C was higher than in all cases. The purification of the induced bacteria was difficultly repeated due to thermal shock, and the purified samples did not have high concentrations. The fluorescence emission of the protein decreased in the presence of the IP3 ligand.
Conclusion: The bacterial expression of IP3-binding domain from human type 2 is weak, but the expression of protein increases with the induction of shock of 42°C.
 

Aims: Hepatitis B is a viral infection, which can cause serious liver problems. Hepatitis B surface antigen (HBsAg), which is produced as recombinant, is used to produce the Hepatitis B vaccine. The aim of this study was to detect DNA aptamer with high affinity against HBsAg by Systematic Evolution of Ligands by Exponential Enrichment (SELEX).
Materials and Methods: In the present experimental study, SELEX method was used to isolate and sequence a DNA aptamer with high affinity against HBsAg. The affinity of this monoclonal nucleotide sequence was calculated by fluorimetric method. The difference of initial absorption and residual value as a measure for the number of associated sequences were calculated with Prism 5 software by nonlinear regression method, Binding-saturation and one site-total model were performed, and the amount of electron affinity (Kd) was determined.
Findings: After performing the SELEX procedure and evaluating the amplified sequence with agarose gel, the result was positive control sample containing a bond in the range of 72nucleotides, indicating successful amplification of the selected sequence, using selective primers. During cloning steps from existing colonies of PCR reaction with aptamer specific primers, the presence of aptamer was confirmed in Escherichia coli bacteria. The reported aptamer had a stable secondary structure with a free energy of ΔG of less than -6.9kJ and T_m higher than 45°C.
Conclusion: The selected DNA aptamer has a high affinity to the target protein (HbsAg) and can be considered as an alternative for mAbs in chromatography column.

Immunotoxins, as a critical approach for cancer therapy, have ability to induction death in cancerous cells based on specific ligands for targeting cancer-specific antigens and toxin domains in its context. Bearing in mind, discovery the cancer-specific antigens, as well as immunotoxin characterization for modeling based on linkers application, is a critical step for drugs design, which is considered in this study for ovarian cancer based on in-silico biology. The results of this study, led to the detection of 29 antigens with expression capacity on the surface of ovarian cancer cells, with the highest and specific expression associated with MAGE4 and CA125 antigens. Moreover, the 3D structure of MAGE4 was performed, and the pattern of its expression was determined to rely on HLA proteins. On the other hand, among connecting proteins to this antigen TRIM69 selected as the most effective ligand. Subsequently, the assembling between the domain of Corynebacterium diphtheria and this ligand with (GGGGS) 3 linker in 5 positions led to the creation of 50 models, with different quality and structure. However, among these models, S4 drug showed the best structure and function including binding affinity and immunogenicity after simulation in physiological condition. Generally, this result led to present the MAGE4 as a suitable candidate for immunotoxin development for ovarian cancer, as well as an effective immunotoxin which should be considered in an experimental condition.