130-50-7Relevant articles and documents
Synthesis of ribonucleotides from the corresponding ribonucleosides under plausible prebiotic conditions within self-assembled supramolecular structures
Franco,Ascenso,Ilharco,Da Silva
supporting information, p. 2206 - 2209 (2020/02/20)
Abiotic synthesis of ribonucleotides, mainly at the 5′ position, from the corresponding ribonucleosides within self-assembled supramolecular structures, based on guanosine:borate hydrogels, was carried out in the temperature range of 70-90 °C, using urea and a phosphate source (K2HPO4 or hydroxyapatite). Phosphorylation is possible at initial concentrations of guanosine lower than 20 mM and it is more efficient using wet/dry cycles. Monoamidophosphate (and, eventually, diamidophosphate), diamidodiphosphate and pyrophosphate are intermediates in the synthesis of ribonucleotides. These conclusions are supported by NMR spectroscopy and mass spectrometry analysis of samples. On the other hand, after reaction, hydrogels can produce globular aggregates by the addition of water and decreasing temperature, thus confirming that ribonucleotides, once activated under suitable conditions, could form polyribonucleotides.
Dinuclear Zn2+ complexes in the hydrolysis of the phosphodiester linkage in a diribonucleoside monophosphate diester.
Yashiro, Morio,Kaneiwa, Hideki,Onaka, Kenichi,Komiyama, Makoto
, p. 605 - 610 (2007/10/03)
Dizinc complexes that were formed from 2:1 mixtures of Zn(NO3)2 and dinucleating ligands TPHP (1), TPmX (2) or TPpX (3) in aqueous solutions efficiently hydrolyzed diribonucleoside monophosphate diesters (NpN) under mild conditions. The dinucleating ligand affected the structure of the aquo-hydroxo-dizinc core, resulting in different characteristics in the catalytic activities towards NpN cleavage. The pH-rate profile of ApA cleavage in the presence of (Zn2+)(2)-1 was sigmoidal, whereas those of (Zn2+)(2)-2 and (Zn2+)(2)-3 were bell-shaped. The pH titration study indicated that (Zn2+)(2)-1 dissociates only one aquo proton (up to pH 12), whereas (Zn2+)(2)-2 dissociates three aquo protons (up to pH 10.7). The observed differences in the pH-rate profile are attributable to the various distributions of the monohydroxo-dizinc species, which are responsible for NpN cleavage. As compared to that using (Zn2+)(2)-1, the NpN cleavage using (Zn2+)(2)-2 showed a greater rate constant, with a higher product ratio of 3'-NMP/2'-NMP. The saturation behaviors of the rate, with regard to the concentration of NpN, were analyzed by Michaelis-Menten type kinetics. Although the binding of (Zn2+)(2)-2 to ApA was weaker than that of (Zn2+)(2)-1, (Zn2+)(2)-2 showed a greater kcat value than (Zn2+)(2)-1, resulting in higher ApA cleavage activity of the former.
The pKa of the internucleotidic 2′-hydroxyl group in diribonucleoside (3′→5′) monophosphates
Acharya,Foeldesi,Chattopadhyaya
, p. 1906 - 1910 (2007/10/03)
Ionization of the internucleotidic 2′-hydroxyl group in RNA facilitates transesterification reactions in Group I and II introns (splicing), hammerhead and hairpin ribozymes, self-cleavage in lariatRNA, and leadzymes and tRNA processing by RNase P RNA, as well as in some RNA cleavage reactions promoted by ribonucleases. Earlier, the pKa of 2′-OH in mono- and diribonucleoside (3′-5′) monophosphates had been measured under various nonuniform conditions, which make their comparison difficult. This work overcomes this limitation by measuring the pKa values for internucleotidic 2′-OH of eight different diribonucleoside (3′-5′) monophosphates under a set of uniform noninvasive conditions by 1H NMR. Thus the pKa is 12.31 (±0.02) for ApG and 12.41 (±0.04) for ApA, 12.73 (±0.04) for GpG and 12.71 (±0.08) for GpA, 12.77 (±0.03) for CpG and 12.88 (±0.02) for CpA, and 12.76 (±0.03) for UpG and 12.70 (±0.03) for UpA. By comparing the pKas of the respective 2′-OH of monomeric nucleoside 3′-ethyl phosphates with that of internucleotidic 2′-OH in corresponding diribonucleoside (3′→5′) monophosphates, it has been confirmed that the aglycons have no significant effect on the pKa values of their 2′-OH under our measurement condition, except for the internucleotidic 2′-OH of 9-adeninyl nucleotide at the 5′-end (ApA and ApG), which is more acidic by 0.3-0.4 pKα units.
