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Abstract: Polygonatum odoratum lectin (POL), a novel mannose-binding lectin with anti-viral and apoptosis-inducing activities, was isolated from rhizomes of Polygonatum odoratum (Mill.) Druce. POL was a homo-tetramer with molecular weight of 11953.623Da per subunits as determined by gel filtration, SDS-PAGE and mass spectrometry. Based on its N-terminal 29-amino acid sequence the full-length cDNA sequence of POL was cloned. Subsequent phylogenetic analysis and molecular modeling revealed that POL belonged to the Galanthus nivalis agglutinin (GNA)-related lectin family, which acquired unique mannose-binding specificity. The hemagglutinating activities of POL were metal ion-independent, and were stable within certain range of pH and temperature alterations. Moreover, POL showed remarkable anti-HSV-II activity towards Vero cells, cytotoxicity towards human melanoma A375 cells and induced apoptosis in a caspase-dependent manner. [Copyright &y& Elsevier]

Abstract: Fas ligand (FasL) is a type II membrane protein and its biologically active soluble form (sFasL) is made by matrix metalloproteinase cleavage. sFasL may induce apoptosis in the Fas-bearing cells and this special biological activity may be applied to cancer therapy. However, it is difficult to obtain recombinant sFasL because of the trimeric form of the protein. In this study, sFasL DNA was fused to the gene of thioredoxin at the amino-terminal and His-tag at the carboxyl terminal before overexpression in Escherichia coli. To restrict the degree of freedom in the subsequent refolding process, recombinant sFasL was dissolved in 6M urea and then immobilized with nickel resin under the denaturing condition. The immobilized recombinant sFasL was incubated with excess denatured sFasL to perform refolding process by dilution under stepwise conditions. After the refolding procedures, stable trimers of sFasL oligomers formed and were identified by gel filtration, co-immunoprecipitation and Western blotting. The sFasL showed biological activities in inducing apoptosis in Fas-expressing T cell and glial cell lines. These findings indicate that preparation of trimer forms of sFasL from E. coli is feasible and this strategy may be useful for large-scale production of sFasL. [Copyright &y& Elsevier]