Protein fusion

As described earlier, translation of the EPSPS mRNA of plants results in the formation of a protein which has an AJ-terminal extension. The AJ-terminal extension, referred to as the chloroplast transit peptide, is necessary and sufficient for the import of the preprotein by the chloroplast. Once imported by the chloroplast, the transit peptide is cleaved releasing the mature enzyme. As expected, introduction of the EPSPS transit peptide to other protein sequences results in the importation of the fusion protein by the chloroplast. 

Another application shows the preparative purification and polishing of a therapeutic fusion protein with a humanized recombinant IgG protein. The fusion protein was expressed by the fermentation of baby hamster kidney cells. The filtered culture supernatant (155 liters) contained 2.2 g of IgG and 75.5 g of total protein. After the immunoglobulins were isolated by expanded bed adsorption and rebuffering, the IgG fraction was bound to Fractogel EMD SOj (M). This column achieved baseline separation of complete antibodies (fusion protein) from small amounts of antibodies lacking the fusion part. The resulting highly purified IgG fraction (110 ml) was diluted to 150 ml and... 

Gene Fusion Systems for Isolation of Cloned Fusion Proteins ... 

What is the amino acid sequence of the fusion protein Where is the junction between /3-galactosidase and the sequence encoded by the insert (Consult the genetic code table on the inside front cover to decipher the amino acid sequence.)... 

J. S. Pati ick and A. L. Lagu, Determination of recombinant human proinsulin fusion protein produced in Escherichia coli using oxidative sulfitolysis and two-dimensional HPLC, Chem. 64 507-511 (1992). 

Escher, A., O Kane, D. J., Lee, J., and Szalay, A. A. (1989). Bacterial luciferase a(3 fusion protein is fully active as a monomer and highly sensitive in vivo to elevated temperature. Proc. Natl. Acad. Sci. USA 86 6528-6532. 

Currently, five different molecular classes of mdr efflux pumps are known [5], While pumps of the the ATP-binding cassette (ABC) transporter superfamily are driven by ATP hydrolysis, the other four superfamilies called resistance-nodulation-division (RND), major facilitator superfamily (MFS), multidrug and toxic compound extrusion (MATE), and small multidrag resistance transporter (SMR) are driven by the proton-motive force across the cytoplasmic membrane. Usually a single pump protein is located within the cytoplasmic membrane. However, the RND-type pumps which are restricted to Gram-negative bacteria consist of two additional components, a periplasmic membrane fusion protein (MFP) which connects the efflux pump to an outer... 

Biologicals. Figure 3 Fusion protein construction combination of the molecular component of interest with the constant region (Fc) of an antibody molecule, usually immunoglobulin (lg)G1 Fc, imparts the Fc function on to the molecularcomponentfortherapeutic use. The example given is ofCTLA4-lg, derivatives of which have shown clinical efficacy in the treatment of rheumatoid arthritis and transplant rejection. 

The list of MoAb or fusion proteins used in treatment of every type of cancer is continually growing as research identifies more cancer-associated antigens. MoAb targeting a tumor-specific antigen is used... 

Inhibition of hematopoietic growth factors Imatinib (Glivec ) is applied to treat chronic myeloid leukemia in Philadelphia-chromosome positive patients. In these patients, translocation of parts of chromosomes 9 and 22 results in the expression of a fusion protein with increased tyrosine kinase activity, called Bcr-Abl. Imatinib is a small Mw inhibitor selective for the tyrosine kinase activity of Bcr-Abl. Thereby, it inhibits the Bcr-Abl induced cell cycle progression and the uncontrolled proliferation of tumor cells. 

Recombinant soluble TNF-RI-IgGl fusion protein Etanercept, Enbrel is a chimeric molecule consisting of the extracellular domain of the TNF receptor I (TNF-RI) and the Fc portion of human IgGl. Two Fc domains are bound to each other via disulfide bonds, thereby yielding dimers with two binding sites for the TNF trimer. Etanercept binds with high affinity to extracellular TNF and reduces TNF activity. Etanercept is not effective in Crohn s disease, possibly because it does not lead to destiuction of membrane TNF-a expressing cells. Indications and side effects are similar to those of Infliximab and Adalimumab. 

This is an immunoglobulin fusion protein with the cytotoxic lymphocyte antigen 4 (CTLA-4) receptor. By binding to CD80/86 on APCs it inhibits the CD28 costimulatory signal in lymphocytes. It is speculated that this can result in tolerance but up to now there is only experimental data [3,4]. 

Alefacept is a human recombinant integrin LFA3-IgG fusion protein that binds to the CD2 receptor thus blocking T-cell activation. 

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