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  • 1
    Electronic Resource
    Electronic Resource
    Prebiotic syntheses of the RNA bases: A critical analysis (1996)
    Springer
    Origins of life and evolution of the biospheres 26 (1996), S. 238-239 
    Details
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02459733
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  • 2
    Electronic Resource
    Electronic Resource
    The improbability of prebiotic nucleic acid synthesis (1984)
    Springer
    Origins of life and evolution of the biospheres 14 (1984), S. 565-570 
    Details
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Many accounts of the origin of life assume that the spontaneous synthesis of a self-replicating nucleic acid could take place readily. Serious chemical obstacles exist, however, which make such an event extremely improbable. Prebiotic syntheses of adenine from HCN, of D, L-ribose from adenosine, and of adenosine from adenine and D-ribose have in fact been demonstrated. However these procedures use pure starting materials, afford poor yields, and are run under conditions which are not compatible with one another. Any nucleic acid components which are formed on the primitive earth would tend to hydrolyze by a number of pathways. Their polymerization would be inhibited by the presence of vast numbers of related substances which would react preferentially with them. It appears likely that nucleic acids were not formed by prebiotic routes, but are later products of evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00933705
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  • 3
    Electronic Resource
    Electronic Resource
    Prebiotic ribose synthesis: A critical analysis (1986)
    Springer
    Origins of life and evolution of the biospheres 16 (1986), S. 283-284 
    Details
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02422027
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  • 4
    Electronic Resource
    Electronic Resource
    Prebiotic ribose synthesis: A critical analysis (1988)
    Springer
    Origins of life and evolution of the biospheres 18 (1988), S. 71-85 
    Details
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The discovery of catalytic ability in RNA has given fresh impetus to speculations that RNA played a critical role in the origin of life. This question must rest on the plausibility of prebiotic oligonucleotide synthesis, rather than on the properties of the final product. Many cliams have been published to support the idea that the components of RNA were readily available on the prebiotic earth. In this article, the literature cited in support of the prebiotic availability of one subunit, D-ribose, is reviewed to determine whether it justifies the claim. Polymerization of formaldehyde (the formose reaction) has been the single reaction cited for prebiotic ribose synthesis. It has been conducted with different catalysts: numerous basic substances, neutral clays and heat, and various types of radiation. Ribose has been identified (yields are uncertain, but unlikely to be greater than 1%) in reactions run with concentrated (0.15 M or greater) formaldehyde. It has been claimed in reactions run at lower concentration, but characterization has been inadequate, and experimental details have not been provided. The complex sugar mixture produced in the formose reaction is rapidly destroyed under the reaction conditions. Nitrogenous substances (needed for prebiotic base synthesis) would interfere with the formose reaction by reacting with formaldehyde, the intermediates, and sugar products in undesirable ways. The evidence that is currently available does not support the availability of ribose on the prebiotic earth, except perhaps for brief periods of time, in low concentration as part of a complex mixture, and under conditions unsuitable for nucleoside synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01808782
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  • 5
    Electronic Resource
    Electronic Resource
    The prebiotic role of adenine: A critical analysis (1995)
    Springer
    Origins of life and evolution of the biospheres 25 (1995), S. 83-98 
    Details
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Adenine plays an essential role in replication in all known living systems today, and is prominent in many other aspects of biochemistry. It occurs among the products of oligomerization of HCN. These circumstances have stimulated the idea that adenine was a component in a replication system that was present at the start of life. Such replicators have included not only RNA, but also a number of simpler RNA-like alternatives which utilize a simpler backbone. Despite these encouraging indicators, a consideration of the chemical properties of adenine reveals reasons that disfavor its participation in such a role. These properties include the following: (1) Adenine synthesis requires HCN concentrations of at least 0.01 M. Such concentrations would be expected only in unique circumstances on the early Earth. Adenine yields are low in prebiotic simulations, and if a subsequent high-temperature hydrolysis step is omitted, the reported yield does not represent adenine itself, but 8-substituted adenines and other derivatives. (2) Adenine is susceptibile to hydrolysis (the half life for deamination at 37 °C, pH 7, is about 80 years), and to reaction with a variety of simple electrophiles, forming a multiplicity of products. Its accumulation would not be expected over a geological time scale, and its regioselective incorporation into a replicator appears implausible. (3) The adenine-uracil interaction, which involves two hydrogen bonds (rather than three, as in guanine-cytosine pairing) is weak and nonspecific. Pairing of adenine with many other partners has been observed with monomers, synthetic oligonucleotides and in RNA. The hydrogen-bonding properties of adenine appear inadequate for it to function in any specific recognition scheme under the chaotic conditions of a prebiotic soup. New and fundamental discoveries in the chemistry of adenine would be needed to reverse this perception. An alternative and attractive possibility is that some other replicator preceeded RNA (or RNA-like substances) in the origin of life.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01581575
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  • 6
    Electronic Resource
    Electronic Resource
    Modification of polyuridylic acid by bisulfite. II: Studies on ribosomal binding and enzymatic hydrolysis (1973)
    Springer
    Molecular biology reports 1 (1973), S. 123-127 
    Details
    ISSN: 1573-4978
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The reaction of polyuridylic acid with sodium bisulfite produces modified polymers in which up to 95% of the uracil residues have been converted to uracil-6-sulfonate residues. A 91.6% bisulfite-saturated polymer was found to resist hydrolysis by spleen phosphodiesterase and phosphorolysis by polynucleotide phosphorylase. Digestion by pancreatic ribonuclease was successful and gave the bisulfite adduct of uridine-3′-phosphate. Treatment of this nucleotide adduct with acid phosphatase afforded the bisulfite adduct of uridine. The ability of polyuridylic acid to bind to ribosomes, and to stimulate the binding of phenylalanine tRNA to ribosomes was abolished by progressive bisulfite saturation of the polymer. The rate of decline of these functionsf with increasing bisulfite content, was less sharp than the loss of phenyl-alanine coding ability o, the modified polymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00357592
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  • 7
    Electronic Resource
    Electronic Resource
    A comparison of the predicted and X-ray structures of angiogenin. Implications for further studies of model building of homologous proteins (1994)
    Springer
    The protein journal 13 (1994), S. 649-658 
    Details
    ISSN: 1573-4943
    Keywords: X-ray crystallography ; computer modeling ; angiogenin ; ribonuclease A
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The three-dimensional structure of human angiogenin has been determined by X-ray crystallography and is compared here with an earlier model which predicted its structure, based on the homology of angiogenin with bovine pancreatic ribonuclease A. Comparison of the predicted model and crystal structure shows that the active-site histidine residues and the core of the angiogenin molecule, including most of theβ-strands andα-helices, were predicted reasonably well. However, the structure of the surface loop regions and residues near the truncated C-terminus differs significantly. The C-terminal segment includes the active-site residues Asp-116, Gln-117, and Ser-118; Gln-117 in particular has been shown to be important in affecting the ribonucleolytic activity of angiogenin. Also, the orientation of one helix in the model differed from the orientation observed experimentally by about 20°, resulting in a large displacement of this chain segment. The difficulty encountered in predicting the surface loop regions has led to a new algorithm [Palmer and Scheraga (1991),J. Comput. Chem.,12, 505–526; (1992),J. Comput. Chem.,13, 329–350] for predicting the conformations of surface loops.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01890464
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  • 8
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    Modification of polyuridylic acid by bisulfite. II: Studies on ribosomal binding and enzymatic hydrolysis (1973)
    Springer
    Details
    Publication Date: 1973-08-01
    Print ISSN: 0301-4851
    Electronic ISSN: 1573-4978
    Topics: Biology
    Published by Springer
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  • 9
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    Prebiotic ribose synthesis: A critical analysis (1986)
    Springer
    Details
    Publication Date: 1986-09-01
    Print ISSN: 0169-6149
    Electronic ISSN: 1573-0875
    Topics: Biology , Geosciences
    Published by Springer
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  • 10
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    Prebiotic ribose synthesis: A critical analysis (1988)
    Springer
    Details
    Publication Date: 1988-03-01
    Print ISSN: 0169-6149
    Electronic ISSN: 1573-0875
    Topics: Biology , Geosciences
    Published by Springer
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