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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 3 (1974), S. 115-120 
    ISSN: 1432-1432
    Keywords: Adenosine Cyclic 2′, 3′-Phosphate ; Polymerization ; 1, 2-Diaminoethane ; Oligonucleotides ; Prebiotic ; Gel Permeation ; Ion Exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adenosine cyclic 2′, 3′-phosphate has been polymerized at room temperature in the dry state using 1, 2-diaminoethane at alkaline pH as catalyst. The high molecular weight products have been analyzed by several different methods, including ion exchange and gel permeation chromatography and phosphate end-group analysis. Gel permeation chromatography showed that between 3.6% and 8.1% of material higher than the hexamer was formed in 3-, 15- and 40-day reactions. The material from a large-scale, 3-day reaction mixture was first fractionated by ion exchange chromatography and the highest molecular weight material then further fractionated by gel permeation chromatography. End-group analysis on the fractions obtained by this procedure showed that 0.67% of the total reaction mixture was polymer with an average chainlength of 13.4; a trace (0.15%) of higher polymer was also formed, but there was insufficient to determine its average chainlength. The prebiological relevance of these findings is discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 3 (1974), S. 141-150 
    ISSN: 1432-1432
    Keywords: Adsorption ; Clay ; Montmorillonite ; Phosphoramidates ; Polymerization ; Prebiotic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nucleoside phosphoramidates derived from polyamines containing at least three amine groups are strongly adsorbed by sodium and magnesium montmorillonite clays even from very dilute solutions. Heating the dried clay-phosphoramidate mixture results in the production of small amounts of the dinucleotides.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 2 (1973), S. 303-316 
    ISSN: 1432-1432
    Keywords: Polymerization ; Phosphorylation ; Adenosine Cyclic 2′,3′-phosphate ; Oligonucleotides ; Amines ; 2-Aminoethanol ; Amino Acids ; Prebiotic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When adenosine cyclic 2′,3′-phosphate is evaporated from solution in the presence of simple catalysts such as aliphatic diamines at alkaline pH, and maintained in a dry state at moderate temperatures (25-85°C), self-polymerization to give oligonucleotides of chainlength up to at least 6 is observed. The products contain an excess of [3′→5′]-linkages over [2′→5′]-linkages. The effects of different catalysts and reaction conditions on the efficiency of the reaction are described. The prebiological relevance of these reactions is discussed.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 13 (1979), S. 203-214 
    ISSN: 1432-1432
    Keywords: Adenosine 5′-phosphorimidazolide ; Oligoadenylates ; Poly(U)-directed condensation ; Pb2+ ion catalysis ; Isomer ratios ; Prebiotic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Pb2+ ion is an effective catalyst for the template-directed condensation of ImpA on poly(U). This reaction generates up to 35% of oligomers 5 or more units long. Furthermore, the product is predominantly 3′–5′-linked (75%) unlike that from the uncatalyzed reaction which is more than 90% 2′–5′-linked. The significance of metal-ion catalysis for prebiotic polynucleotide formation is discussed.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 12 (1979), S. 237-257 
    ISSN: 1432-1432
    Keywords: Oligoadenylates ; Phosphorimidazolides ; Template-directed polycondensation ; Isomer ratios ; Prebiotic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have studied a variety of condensation reactions involving poly (U) as template and isomeric adenosine dinucleotides as substrates. We find that [3′–5′]-linked dinucleotides such as A3pA and pA3pA are better acceptors than the corresponding [2′–5′]-linked compounds, while ImpA2pA is a better donor than ImpA3pA. The reaction between A2pA and ImpA3pA, for example, yields only 4% of product while the reaction of A3pA with ImpA2pA yields 86% of product. The more efficient condensation reactions of dimers are about as efficient as the self-condensation of ImpA. They yield a few percent of material in which five or more substrate molecules are linked together. The percentage of the natural [3′–5′]-linkage in the product varies greatly, from as little as 1% to as much as 45%.
    Type of Medium: Electronic Resource
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