Synthesis of Poly ribonucleotides

By a similar approach, a pentanucleoside tetraphosphate, UpApm2GpCpC, corresponding to nucleotides 8-12 in yeast tRNATyr was synthesized by stepwise additions 289 The yields from the condensations were 75, 38, 31, and 21%, respectively. This work has been ex- 

Single addition reactions to primer oligonucleotides, catalyzed by polynucleotide phosphorylase (EC 2.7.7.8), have been reported using 2 (3 )-0-substituted nucleoside 5 -diphosphate, where, apparently, the 2 -substituent prevents further reaction at the free 3 -hydroxyl group.302 Almost quantitative yields have been obtained by use of 

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Several triester approaches to the synthesis of oligo(ribonucleo-tides) have been adopted that are distinguished by the different 

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The use of DNA ligase for the synthesis of double-stranded poly(deoxyribonucleotides) has been described in Section IV,6, and its use for analogous joining of poly(ribonucleotides) has also been... 

Besides classical resin beads, other polymeric carriers were also used for the synthesis ofpeptide libraries in various formats. Poly aery late-grafted polypropylene pins were used for the synthesis of the first combinatorial chemical library [1,2], This type of support continues to be heavily used in multiple peptide [27] and non-peptide [28] library synthesis. Cellulose paper, originally used by Frank et al. as a solid-phase support for oligodeoxy-ribonucleotide synthesis [29], has also been used as the support for multiple SPOT synthesis of peptide libraries [30,31], Polystyrene-grafted polyethylene film (PS-PE) may also be used in combinatorial peptide library synthesis [32], The specific feature of the membrane type of carrier is its dividability. This feature has been used for the synthesis of libraries with a nonstatistical distribution of library members, where no compound is missing and none is represented more than once [33],... 

The Chemical Synthesis of Oligo- and Poly-ribonucleotides. Reese, C. B. In Nucleic Acids and Molecular Biology Eckstein F, Li He y, D, M. J., Eds. Springer Berlin, 1989 164. 

Rao MV, Reese CB, Schehlmann V, Yu PS. Use of the l-(2-fluorophenyl)-4-methoxypiperidin-4-yl (Fpmp) protecting group in the solid-phase synthesis of oligo- and poly-ribonucleotides. J Chem Soc Perkin Trans I 43-55, 1993. 

Furthermore, in the case of rifampicin (=rifampin, a synthetic rifamycin derivative) the resistance was localized in the p-subvinit of the RNA-poly-merase. Binding of rifamycin to RNA-polymerase from bacterial sensitive strains has been found under varied experimental conditions, while the antibiotic does not bind to the enzyme from resistant strains, Rifamycin does not prevent the interaction of RNA-polymerase with template DNA , The antibiotic blocks the addition of the first ribonucleotide at the initiation of synthesis of an RNA chain by RNA-polymerase. but it cannot inhibit the synthesis of an RNA chain once it has been started On the other hemd, streptolydigin appears to inhibit elongation of RNA syn-thesis , RNA-polymerase from rat liver mitochondria has also been shown to be sensitive to rifamycin . The RNA-polymerase from blue-green algae was found to be sensitive to rifamycin, but to a lesser extent than the bacterial enzyme... 

Theoretically, it may be possible to artificially increase the production of interferon by the action of an inducer. Synthetic double-stranded ribonucleotide polymers, in particular the double-helical complex of polyinosinic acid with poly-cytidylic acid RNA (poly IC) are used in this way These agents activate the synthesis of interferon. They increase the resistance to viruses of cells m culture, and promote recovery in rabbits suffering from herpetic eye infection. This type of activity is an important prospect in the field of antiviral therapy. 

Synthetic polymers containing either desoxyribonucleotide or ribonucleotide strands are known to stimulate the in vitro DNA synthesis by RNA tumor viruses. Some inhibitors of the DNA-polymerase reaction in RNA tumor viruses are known to exhibit a template-primer specificity6, 7 34 Table 22 shows the inhibition of template-dependent DNA polymerase activity of FLV by DEAE-F at various concentrations. The reaction catalyzed by poly (dl - dC) is most strongly stimulated by DEAE-F. Thus at 20 pg/reaction mixt. of DEAE-F the incorporation of 3H—dGMP is almost 4 times that of control. 

If all four 5 -triphosphates are present in vitro (d-ATP, d-CTP, d-GTP, and d-TTP), as well as a single-stranded DNA template (matrix), magnesium ions, and the enzyme DNA-polymerase, then high-molecular-weight poly(d-ribonucleotides) are produced. Since DNA synthesis will not occur without the DNA template, the template may be referred to as the primer. The composition and sequence of this newly formed DNA correspond to those of the native primer DNA, i.e., the DNA that was initially added. The DNA polymerase (Kornberg enzyme) may be obtained from Escherichia coli and added as a cell-free extract. 

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