guanosine-monophosphate and guanylyl-(3--5-)-guanosine

For deeper understanding the roles of the mRNA cap structure in cellular processes isotopically labeled dinucleotide cap analogues have been synthesized as tools for NMR and in vivo studies. Tritium or carbon C-13 labeled methyl iodide was used as a source of the isotope material. In order to minimize the number of steps during the radioisotopic synthesis the methylation with tritium labeled methyl iodide was performed with Gp(3)G as a substrate. The C-13 isotope was introduced into the cap dinucleotide by methylation of GDP with C-13 Methyl iodide, followed by coupling the product with guanosine 5'-phosphorimidazolide in DMF with zinc chloride as a catalyst.

Topics: Carbon Isotopes; Catalysis; Dinucleoside Phosphates; Guanosine Monophosphate; Hydrocarbons, Iodinated; Isotope Labeling; Methylation; Nuclear Magnetic Resonance, Biomolecular; RNA Caps; RNA, Messenger; Tritium

The tetramethylammonium salt of guanylyl-(3'-5')-guanosine has been prepared by a cation-exchange technique and it has been found that the tetramethylammonium ion drastically reduces the self-association of GpG in solution. This has allowed the characterization of GpG by FTIR and 1-D and 2-D NMR spectroscopy. A complete, well-resolved 1H NMR spectrum in D2O has been obtained and all resonances have been assigned. A weak, essentially non-cooperative intermolecular association is observed in solution (15-20 mM) below 40 degrees C. The association occurs via base stacking and base-base hydrogen bonding.

Topics: Chemical Phenomena; Chemistry; Dinucleoside Phosphates; Guanine Nucleotides; Guanosine; Guanosine Monophosphate; Magnetic Resonance Spectroscopy; Quaternary Ammonium Compounds; Salts; Spectrophotometry, Infrared; Temperature

The reaction of three platinum compounds, Pt(NH3)2Cl2, Pt(en)Cl2 and Pt(pn)Cl2 with nucleic acid fragments (Ade, Gua; GpG, GpA and ApA), both reactants (1:1, 1 X 10(-2) M; 1 X 10(-3) M) being dissolved in water, has been studied. UV measurements have been used to characterize the products. Kinetics and adduct formation in the nucleoside-Pt compound system were studied by reversed-phase high-performance liquid chromatography [gradient 0-30% methanol in 30 min, ammonium acetate buffer (0.1 M) at pH 4.25] at fixed intervals of time and the product formation was examined by measuring the peak heights. After 10 h, the reaction was complete for guanosine and showed a steady state for adenosine. The increasing lipophilicity in the sequence of the platinum compounds resulted in a shift to longer retention times.

Topics: Adenosine; Chemical Phenomena; Chemistry; Chromatography, High Pressure Liquid; Dinucleoside Phosphates; Drug Interactions; Guanine Nucleotides; Guanosine; Guanosine Monophosphate; Hydrogen-Ion Concentration; Kinetics; Organoplatinum Compounds; RNA

The three diguanosine phosphates GpG (4 X 10(-4) M), d(GpG) (10(-5) M), and d(pGpG) (10(-5) M) have been reacted with cis-[Pt(NH3)2(H2O)2](NO3)2 (1 Pt/dinucleotide) in water at pH 5.5 and 37 degrees C. In each case a single product is formed. The three complexes have been characterized by proton nuclear magnetic resonance (1H NMR) and circular dichroism (CD) analyses. They are N(7)-N(7) chelates of the metal with an anti-anti configuration of the bases. They present a conformational change upon deprotonation of guanine N(1)H whose pKa is ca. 8.7 (D2O). Their CD spectra, compared to those of the free dinucleotides, exhibit an increase of ellipticity in the 275-nm region, which can be qualitatively related to the characteristic increase reported for platinated DNA and poly(dG) . poly(dC). These results are in favor of the hypothesis of intrastrand cross-linking of adjacent guanines, by the cis-PtII(NH3)2 moiety, after a local denaturation of DNA.

Topics: Chemical Phenomena; Chemistry; Circular Dichroism; Cisplatin; Deoxyguanine Nucleotides; Dinucleoside Phosphates; DNA; Guanine Nucleotides; Guanosine; Guanosine Monophosphate; Magnetic Resonance Spectroscopy; Nucleic Acid Denaturation; Water

A systematic and comparative study was performed on the polypeptide composition and the RNA polymerase activity associated with virions of various strains of influenza A virus, including four human and two avian viruses. Significant differences were found in the molecular weights of not only hemagglutinin (HA) but also both nucleoprotein (NP) and membrane protein (M), as determined by polyacrylamide gel electrophoresis under denaturing conditions. The results indicate that, among viruses sharing the same serotype determined by the surface proteins HA and NA (neuraminidase), considerable variations exist in the structure of viral proteins, including inner proteins. The relative contents of viral proteins also varied among these strains grown under similar conditions. The total content of three P proteins, the putative RNA polymerase subunits, was within the range between 1.1 and 2.2% of total viral proteins and roughly paralleled the virion-associated RNA polymerase activity. The virion-associated RNA polymerase of all the strains tested were stimulated by the same dinucleotide primers, ApG or GpG, indicating that the specificity of transcription initiation is conserved among wide varieties of influenza virus.

Topics: Adenosine Monophosphate; Chemical Phenomena; Chemistry; Dinucleoside Phosphates; DNA-Directed RNA Polymerases; Guanosine; Guanosine Monophosphate; Influenza A virus; Macromolecular Substances; Molecular Weight; Peptides; Species Specificity; Virion

Topics: Adenosine; Cytidine; Dinucleoside Phosphates; Guanosine; Guanosine Monophosphate; Hydrogen-Ion Concentration; Kinetics; Oligoribonucleotides; Ribonuclease T1; Ribonucleases; Substrate Specificity; Uridine