In this paper,we report the chemical synthesis of oligonucleotide d-TGGGT using phosphotriester method.The protected pentamer d-MmtTGibGibGibT(=p-ClC6H_4-O(O)P)was deblocked by treatment with concentrated ammonium hyd...In this paper,we report the chemical synthesis of oligonucleotide d-TGGGT using phosphotriester method.The protected pentamer d-MmtTGibGibGibT(=p-ClC6H_4-O(O)P)was deblocked by treatment with concentrated ammonium hydroxide and 80% acetic acid.The pure d-TGGGT obtained by chromatorgraphy on DEAE-Sephadex A-25 and Q-Sepharose FF could be hydrolyzed completely and confirmed by base ratio.展开更多
A newly discovered enzyme, that can catalyze the formation of phosphotriester/-diester bonds between nucleic acids, was found to be associated with plant and animal viruses; （i.e. southern bean mosaic virus, brome mo...A newly discovered enzyme, that can catalyze the formation of phosphotriester/-diester bonds between nucleic acids, was found to be associated with plant and animal viruses; （i.e. southern bean mosaic virus, brome mosaic virus, influenza virus, avian virus and mouse retrovirus）. A partially purified enzyme from maize developing endosperms was prepared through 15%-35% ammonium sulfate fractionation, DEAE-cellulose anion exchange column chromatography and Sephadex GI50 gel filtration. The enzyme preparation was then used to demonstrate its main functional characteristics. The enzyme can use varieties of short and long chain length of nucleotides as substrates. However, the enzyme requires at least a minimum of 3 to 4 units of nucleotide chain length for the reaction to occur. The enzyme activity shows an optimum reaction in 50 mM sodium acetate buffer at pH 5.4 and is significantly inhibited by 6-azauridine as compared to other nucleotide analogs. By analyzing the data documented in literature and the results from the present study of the association of this enzyme with viruses and the distinctive inhibitory effect of 6-azauridine, it is speculated that this enzyme is likely associated with many other plant and animal viruses. The association of this enzyme on the surface of virus particles can be explored as a common antigen for developing a versatile antiviral vaccine.展开更多
With the help of model experiments, we are able to offer a detailed proposal for the inhibition of DNA duplication and no inhibition of RNA viral infectivity. As a backbone, we introduced methyl phosphotriester (MPTE)...With the help of model experiments, we are able to offer a detailed proposal for the inhibition of DNA duplication and no inhibition of RNA viral infectivity. As a backbone, we introduced methyl phosphotriester (MPTE). Duplex formation according to the traditional Watson and Crick base-pairing: [(MPTE)<sub>n−1</sub> DNA] * DNA and [(MPTE)<sub>n−1</sub> DNA] * RNA, where n = number of DNA and RNA bases. However, in the latter case, inhibition is obtained by reduction of the number of MPTE linkages, as is confirmed with model experiments and under biological conditions with micro (mi)RNA substrates. The latter results have recently been published. One or more single MPTEs are disseminated over different places of DNA without neighbour MPTEs (Prof. Wen-Yih Chen and his group, Taiwan).展开更多
A new strategy for the synthesis of unsymmetrical phosphotriesters was reported: an alcohol was converted to unsymmetrical dialkyl phosphites firstly, which then reacted with the second alcohol or phenol to afford req...A new strategy for the synthesis of unsymmetrical phosphotriesters was reported: an alcohol was converted to unsymmetrical dialkyl phosphites firstly, which then reacted with the second alcohol or phenol to afford required unsymmetrical triesters in the presence of iodine in high yields under exceptionally mild conditions.展开更多
文摘In this paper,we report the chemical synthesis of oligonucleotide d-TGGGT using phosphotriester method.The protected pentamer d-MmtTGibGibGibT(=p-ClC6H_4-O(O)P)was deblocked by treatment with concentrated ammonium hydroxide and 80% acetic acid.The pure d-TGGGT obtained by chromatorgraphy on DEAE-Sephadex A-25 and Q-Sepharose FF could be hydrolyzed completely and confirmed by base ratio.
文摘A newly discovered enzyme, that can catalyze the formation of phosphotriester/-diester bonds between nucleic acids, was found to be associated with plant and animal viruses; （i.e. southern bean mosaic virus, brome mosaic virus, influenza virus, avian virus and mouse retrovirus）. A partially purified enzyme from maize developing endosperms was prepared through 15%-35% ammonium sulfate fractionation, DEAE-cellulose anion exchange column chromatography and Sephadex GI50 gel filtration. The enzyme preparation was then used to demonstrate its main functional characteristics. The enzyme can use varieties of short and long chain length of nucleotides as substrates. However, the enzyme requires at least a minimum of 3 to 4 units of nucleotide chain length for the reaction to occur. The enzyme activity shows an optimum reaction in 50 mM sodium acetate buffer at pH 5.4 and is significantly inhibited by 6-azauridine as compared to other nucleotide analogs. By analyzing the data documented in literature and the results from the present study of the association of this enzyme with viruses and the distinctive inhibitory effect of 6-azauridine, it is speculated that this enzyme is likely associated with many other plant and animal viruses. The association of this enzyme on the surface of virus particles can be explored as a common antigen for developing a versatile antiviral vaccine.
文摘With the help of model experiments, we are able to offer a detailed proposal for the inhibition of DNA duplication and no inhibition of RNA viral infectivity. As a backbone, we introduced methyl phosphotriester (MPTE). Duplex formation according to the traditional Watson and Crick base-pairing: [(MPTE)<sub>n−1</sub> DNA] * DNA and [(MPTE)<sub>n−1</sub> DNA] * RNA, where n = number of DNA and RNA bases. However, in the latter case, inhibition is obtained by reduction of the number of MPTE linkages, as is confirmed with model experiments and under biological conditions with micro (mi)RNA substrates. The latter results have recently been published. One or more single MPTEs are disseminated over different places of DNA without neighbour MPTEs (Prof. Wen-Yih Chen and his group, Taiwan).
基金Project supported by the National Natural Science Foundation of China (No. 29772047).
文摘A new strategy for the synthesis of unsymmetrical phosphotriesters was reported: an alcohol was converted to unsymmetrical dialkyl phosphites firstly, which then reacted with the second alcohol or phenol to afford required unsymmetrical triesters in the presence of iodine in high yields under exceptionally mild conditions.
