Nucleosides Nucleotides
September 1998
Two convenient, practical routes to the synthesis of non-nucleotide bridged cyclic oligonucleotides have been developed. The first procedure included circularization of oligonucleotides by template-directed ligation on solid phase, while the second procedure involved preparation of a circular oligomer by non-template chemical ligation of a linear precursor in solution. Using these approaches, a series of single- and double-stranded cyclic oligonucleotides with non-nucleotide bridges has been synthesized.
View Article and Find Full Text PDFIn an attempt to improve physico-chemical and biological properties of peptide nucleic acids (PNAs), particularly water solubility and cellular uptake, the synthesis of chimeric oligomers consisted of PNA and phosphono-PNA analogues (pPNAs) bearing the four natural nucleobases has been accomplished. To produce these chimeras, pPNA monomers of two types containing N-(2-hydroxyethyl)phosphonoglycine, or N-(2-aminoethyl)phosphonoglycine backbone, were used in conjunction with PNA monomers representing derivatives of N-(2-aminoethyl)glycine, or N-(2-hydroxyethyl)glycine. The oligomers obtained were composed of either PNA and pPNA stretches or alternating PNA and pPNA monomers.
View Article and Find Full Text PDFChemicoenzymatic synthesis and cloning of a gene encoding the Fc domain of human immunoglobulin G1 were carried out. The artificial gene was expressed in Escherichia coli cells in plasmid vectors under control of a late T7 promoter. The recombinant protein isolated from the bacterial cells is capable of forming dimers and binding protein A from Staphylococcus aureus.
View Article and Find Full Text PDFA set of new sulfurizing agents representing disulfides of arylsulfonic acids has been developed for the automated synthesis of phosphorothioate oligonucleotide analogues via the phosphoramidite method. These reagents, such as bis(benzenesulfonyl)disulfide, bis(p-toluenesulfonyl)disulfide, bis(p-methoxybenzensulfonyl)disulfide, and bis (p-chlorobenzenesulfonyl) disulfide, are easily prepared crystalline solid compounds. They are relatively inexpensive, easy to handle, and efficiently convert internucleotide cyanoethyl phosphite to the phosphorothioate triester within 1-2 min.
View Article and Find Full Text PDFPlasmid vectors providing a high level expression in Escherichia coli cells of genes for heterologous polypeptides and proteins fused to peptides containing homohistidine clusters have been constructed. The obtained vectors have been used to achieve expression of genes for streptavidin, proinsulin and calcitonin. The hybrid proteins were isolated by affinity chromatography on Ni-agarose columns.
View Article and Find Full Text PDFBecause of the potential significance of the 'molecular recognition' theory for studies in molecular biology and biotechnology, the theory is worth being examined using methods of chemical-enzymatic gene synthesis, recombinant DNA construction and microbiological peptide synthesis. We therefore undertook the synthesis of human Va18-calcitonin, miniproinsulin, and the corresponding antisense peptides as model compounds. In designing an experimental system the idea was to combine sense and antisense polypeptides into a single chain and to examine their intramolecular interaction.
View Article and Find Full Text PDFDipentafluorophenyl carbonate has been successfully used as condensing agent for the internucleotide bond formation in the synthesis of oligonucleotides via H-phosphonate approach. The mechanism of a nucleotide component activation with this reagent has been investigated with the help of 31P NMR spectroscopy. It was shown that preactivation of deoxynucleoside H-phosphonate with dipentafluorophenyl carbonate has no influence on the efficiency of the synthesis.
View Article and Find Full Text PDFStudies on the development of encephalitogenic activity in the cerebral tissue of various animals (rabbits, rats, mice and sheep) showed that the brains of albino rats did not become encephalitogenic until after the 18th day of life, which is later than in any of the other animals studied. On the basis of this finding, a method was developed for the preparation of an entirely allergen-free, non-encephalitogenic antirabies vaccine using the brains of suckling rats. The phenolized vaccine, both in liquid and in lyophilized form, consistently gave high antigenic titres when tested in animals and produced a good increase in virus-neutralizing antibodies in man.
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