Polyadenylic acid

After more than 20 years, Walde et al. (1994) returned in a way to coacervate experiments, although using other methods. Walde (from the Luisi group) repeated nucleotide polymerisation of ADP to give polyadenylic acid, catalysed by polynucleotide phosphorylase (PNPase). But instead of Oparin s coacervates, the Zurich group used micelles and self-forming vesicles. They were able to demonstrate that enzyme-catalysed reactions can take place in these molecular structures, which can thus serve as protocell models. Two different supramolecular systems were used ... 

Table 5.24. 13C Chemical Shifts (6C in ppm) of Randomly Coiled Poly(8-bromoadenylic Acid), Polyadenylic Acid and Corresponding 5 -Mononucleotides Temperature 70 °C Solvent D2Q, pD 7.0-7.3 [781],...

Hankiewicz E (1995) Hydroxyl radical-induced reactions in polyadenylic acid as studied by pulse radiolysis II. Reactions of primary radicals with oxidants. Bull Pol Acad Sci Chem 43 41-49 Hankiewicz E (1996) Hydroxyl radical-induced reactions in polyadenylic acid as studied by pulse radiolysis - Part III. Consecutive reactions. Radiat Phys Chem 47 61-65 Hankiewicz E (1998) Hydroxyl radical-induced reactions in polyadenylic acid as studied by pulse radiolysis. IV. Reactions of primary radicals with reductants. Bull Pol Acad Sci Chem 46 455-464 Hankiewicz E, Bothe E, Schulte-Frohlinde D (1992) Hydroxyl radical-induced reactions in polyadenylic acid as studied by pulse radiolysis, part. I. Transformation reactions of two isomeric OH-adducts. Free Rad Res Commun 16 391-400... 

In order to obtain information about the origin of the peak at + 0.45 V, the GCE surface was modified with DNA-like sequences (po-lyguanylic and polyadenylic acids) that contain or not guanine residues [35]. These new types of biosensors were incubated in a quercetin solution and then conditioned (see Procedure 29 in CD accompanying this book). In this way, it was shown that the peak at + 0.45 V is directly related with the presence of guanine residues in the polynucleotidic chain and that it is due to the formation of 8-oxodGuo. 

Formation of oligopeptides of each of four amino acids in suspension of nucleo-proteinoid microparticles composed of polyadenylic acid and lysine-rich proteinoid has been studied. Amino acids are each converted to peptides by the nucleoproteinoid microparticles in suspension, at rates that differ in minor degree for the various amino acids 28). 

Jacobsen, J. V. Zwar, J. A. Gibberellic acid and RNA synthesis in barley aleurone layers metabolism of rRNA and tRNA and of RNA containing polyadenylic acid sequences. 

Eukaryotic mRNAs often have long 3 untranslated sequences— sequences that follow the stop codon for the protein they encode. These mRNAs generally conclude with a sequence of up to 200 adenosines, the polyadenylic acid (polyA) sequence at the 3 end. This sequence isn t coded by the DNA template for the gene it is added post-transcriptionally. Not all mRNAs are polyadenylated. For example, histone mRNAs lack polyA tails. Polyadenylation seems to play a role in regulating the stability of mRNAs. An early event in the breakdown of some mRNAs is the removal of their polyA tails. 

To demonstrate polymerase activity in a model cell, Chakrabarti et al. [79] encapsulated polynucleotide phosphorylase in vesicles composed of dimyris-toylphosphatidylcholine (DMPC). This enzyme can produce RNA from nucleoside diphosphates such as adenosine diphosphate (ADP) and does not require a template, so it has proven useful for initial studies of encapsulated polymerase activity (Fig. 10a). Furthermore, DMPC liposomes are sufficiently permeable so that 5-10 ADP molecules per second enter each vesicle. Under these conditions, measurable amounts of RNA in the form of polyadenylic acid were synthesized and accumulated in the vesicles after several days incubation. The enzyme-catalyzed reaction could be carried out in the presence of a protease external to the membrane, demonstrating that the vesicle membrane protected the encapsulated enzyme from hydrolytic degradation. Similar behavior has been observed with monocarboxylic acid vesicles [80], and it follows that complex phospholipids are not required for an encapsulated polymerase system to function. 

Growing membrane systems have been used to obtain artificial infrabiological systems. Walde et al. [47] have carried out the synthesis of polyadenylic acid in self-reproducing vesicles [48], in which the enzyme polynucleotide phosphorylase carried out the synthesis of poly-A, and membrane vesicle multiplication was due to the hydrolysis of externally provided oleic anhydride to oleic acid. The snag is that the enzyme component is not auto-catalytic. Enzymatic RNA replication in vesicles [49] suffers from the same problem. It is also not known whether redistribution of the entrapped enzymes into newly formed vesicles occurs or not. An affirmative answer would be evidence for vesicle reproduction by fission. 

Poly A Sepharose Polyadenylic acid mRNA-binding proteins Viral RNA, RNA polymerase Pharmacia... 

Rich A, Davies DR, Crick FHC, Watson JD (1961) The molecular structure of polyadenylic acid. J Mol Biol 3 71-86... 

RNA and synthetic polyribonucleotides that, like RNA, contain ribose as the sugar component but, unlike RNA, contain only one of the four bases in a polymeric chain (e.g., polyadenylic acid, or poly A). 

Figure 4. Depolymerization of polyadenylic acid by divalent ions...

Subsequently, Krampitz (50b) reported that pyruvic, phenylpyruvic, or oxalacetic acid can replace a-ketoglutaric acid in the amination system to form alanine, phenylalanine, and aspartic acid, respectively. Urea could be replaced with nicotinamide, adenine, adenosine, AMP, ADP, ATP, polyadenylic acid, RNA, DNA, and ammonium salts. 

Figure 7. Phosphorescence quenching in polyadenylic acid, data recalculated after Eislnger und Schulman (61)...

Raszka, M. and Mandel, M., Interaction of aromatic amino acids with neutral polyadenylic acid, Proc. Natl. Acad. Sci. U.S.A., 68(6], 1190, 1971. 

Murty, C. N., Verney, E., and Sidransky, H., Effect of tryptophan on polyribo-adenylic acid and polyadenylic acid-messenger ribonucleic acid in rat liver, Lab. Invest., 34[1], 77, 1976. 

Smuckler, E. A. and Koplitz, R. M., Polyadenylic acid content and electrophoretic behavior of in vitro released RNAs in chemical carcinogenesis, Cancer Res., 36[3], 881, 1976. 

This reaction was reported for the benzophenone photosensitized degradation of polypropylene (92),polystyrene (95), poly(vinyl alcohol) (94),polyisoprene (95,96),polyurethane (97) and polyadenylic acid (98) In solid state benzophenone also produce an extensive crosslinking of polyethylene (99-105) It has also been found that benzophenone and its derivatives caused an initial rapid oxidation,increasing with ketone concentration (70) Currently the relative importance of singlet oxygen formation in energy transfer reaction between excited benzophenone and molecular oxygen is discussed (92,104) ... 

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