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  • 1
    Electronic Resource
    Electronic Resource
    Aminoacyl transfer from an adenylate anhydride to polyribonucleotides (1975)
    Springer
    Journal of molecular evolution 6 (1975), S. 309-320 
    Details
    ISSN: 1432-1432
    Keywords: Aminoacyl Transfer ; Amino Acid Adenylate ; Imidazole Catalysis ; Evolution ; Peptide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Imidazole catalysis of phenylalanyl transfer from phenylalanine adenylate anhydride to the hydroxyl groups of homopolyribonucleotides was investigated as a chemical model of the biochemical aminoacylation of tRNA. Imidazole catalyzed transfer of phenylalanine to poly (U) increases from pH 6.5 to 7.7 and decreases above pH 7.7. At pH 7.7 approximately 10% of the phenylalanyl residues are transferred to poly (U). At pH 7.1, transfer to poly (U) was five times as great as to poly (A) and transfer to a poly (A) poly (U) double helix was negligible. At pH 7.1 approximately 45 mole percent linkages to poly (U) were monomeric phenylalanine; the remainder of the linkages were peptides of phenylalanine. The number of linkages and their lability to base and neutral hydroxylamine indicates that phenylalanine and its peptides are attached as esters to the 2′ hydroxyl groups throughout poly (U) and the 2′ (3) hydroxyl groups at the terminus of poly (U). These results do model the contemporary process of aminoacyl transfer to tRNA and continue to suggest that a histidine residue is in the active site of aminoacyl-tRNA-synthetases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01794637
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  • 2
    Electronic Resource
    Electronic Resource
    Energy from Redox Disproportionation of Sugar Carbon Drives Biotic and Abiotic Synthesis (1997)
    Springer
    Journal of molecular evolution 44 (1997), S. 354 -360 
    Details
    ISSN: 1432-1432
    Keywords: Key words: Biosynthesis — Fermentation — Bioenergetics — Origin of metabolism — Prebiotic synthesis — Origin of life — Molecular evolution — Reduction-oxidation — Sugar chemistry — Free energy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. To identify the energy source that drives the biosynthesis of amino acids, lipids, and nucleotides from glucose, we calculated the free energy change due to redox disproportionation of the substrate carbon of (1) 26-carbon fermentation reactions and (2) the biosynthesis of amino acids and lipids of E. coli from glucose. The free energy (cal/mmol of carbon) of these reactions was plotted as a function of the degree of redox disproportionation of carbon (disproportionative electron transfers (mmol)/mmol of carbon). The zero intercept and proportionality between energy yield and degree of redox disporportionation exhibited by this plot demonstrate that redox disproportionation is the principal energy source of these redox reactions (slope of linear fit =−10.4 cal/mmol of disproportionative electron transfers). The energy and disproportionation values of E. coli amino acid and lipid biosynthesis from glucose lie near this linear curve fit with redox disproportionation accounting for 84% and 96% (and ATP only 6% and 1%) of the total energy of amino acid and lipid biosynthesis, respectively. These observations establish that redox disproportionation of carbon, and not ATP, is the primary energy source driving amino acid and lipid biosynthesis from glucose. In contrast, we found that nucleotide biosynthesis involves very little redox disproportionation, and consequently depends almost entirely on ATP for energy. The function of sugar redox disproportionation as the major source of free energy for the biosynthesis of amino acids and lipids suggests that sugar disproportionation played a central role in the origin of metabolism, and probably the origin of life.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00006154
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  • 3
    Electronic Resource
    Electronic Resource
    Oligoglyceric acid synthesis by autocondensation of glyceroyl thioester (1987)
    Springer
    Journal of molecular evolution 25 (1987), S. 191-196 
    Details
    ISSN: 1432-1432
    Keywords: Glyceroyl thioester ; Polymerization ; Polyester ; Oligoglyceric acid ; Thioester ; Prebiotic chemistry ; Molecular evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The autocondensation of the glyceroyl thioesterS-glyceroyl-ethanethiol yielded oligoglyceric acid. The rates of autocondensation and hydrolysis of the thioester increased from pH 6.5 to pH 7.5 in 2,6-lutidine and imidazole buffers. Autocondensation and hydrolysis were much more rapid in imidazole buffers than in 2,6-lutidine buffers of the same pH. The efficiency of ester bond synthesis was about 20% for 40 mMS-glyceroylethanethiol in 2,6-lutidine and imidazole buffers near neutral pH. The size and yield of the oligoglyceric acid products increased when the concentration of the thioester was increased. The relationship of these results to prebiotic polymer synthesis is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02100011
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  • 4
    Electronic Resource
    Electronic Resource
    The formation of peptides from the 2′(3′)-glycyl ester of a nucleotide (1978)
    Springer
    Journal of molecular evolution 11 (1978), S. 189-198 
    Details
    ISSN: 1432-1432
    Keywords: Aminoacylnucleotides ; Amino acid esters ; Peptides ; Molecular evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have synthesized 2′(3′)-O-(glycyl)-adenosine-5′-(O-methylphos-phate), an analogue of the 3′-terminus of aminoacylated tRNA. A 0.4M solution of this compound maintained at pH 8.2, yields 5.5% of diglycine and 11.5% of diketopiperazine, in addition to the hydrolysis products glycine and adenosine-5′-(O-methylphosphate). Under the same conditions, glycine ethyl ester reacts much more slowly, but ultimately gives similar yields of diglycine and diketopiperazine. The aminolysis of 2′(3′)-O-(glycyl)-adenosine-5′-(O-methylphosphate) by free glycine is relatively inefficient, but serine reacts 20 times more rapidly and yields up to 50% of N-glycylserine. The prebiotic significance of these reactions is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01734480
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  • 5
    Electronic Resource
    Electronic Resource
    Poly(U)-directed peptide-bond formation from the 2′(3′)-glycyl esters of adenosine derivatives (1980)
    Springer
    Journal of molecular evolution 16 (1980), S. 1-10 
    Details
    ISSN: 1432-1432
    Keywords: Aminoacyl ester ; Template ; Polynucleotide ; Molecular evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The self-condensation of 2′(3′)-O-glycyl esters of adenosine, adenosine-5′-(O-methylphosphate) and P1, P2-diadenosine-5′-pyrophosphate in 6.2 mM solutions at pH 8.0 and -5°C in the presence of 12.5 mM poly(U) yields approximately 3 times as much diketopiperazine as reactions without poly(U). As the concentration of 2′(3′)-O-(glycyl)-P1, P2-diadenosine-5′-pyrophosphate is decreased from 6.2 mM to 1.5 mM the yield of diketopiperazine in the presence of poly(U) decreases slightly from 6.6% to 5.2%, whereas, in the absence of poly(U) the yield of diketopiperazine decreases substantially from 2.4% to 0.75%. The enhanced yield of diketopiperazine that is attributed to the template action of poly(U) is temperature dependent and is observed only at temperatures below 10°C (5°C to -5°C) for 6.2 mM 2′(3′)-O-(glycyl)-adenosine-5′-(O-methylphosphate) and below 23°C (15°C to -5°C) for 6.2 mM 2′(3′)-O-(glycyl)-P1, P2-diadenosine-5′-pyrophosphate. The absence of a template effect at high temperatures is attributed to the melting of the organized helices. The hydrolysis half-lives at pH 8.0 and -5°C of 2′(3′)-O-(glycyl)-adenosine, 2′(3′)-O-(glycyl)-adenosine-5′-(O-methylphosphate), 2′(3′)-O-(glycyl)-P1, P2-diadenosine-5′-pyrophosphate, and 5′-O-(glycyl)-adenosine in the presence of poly(U) are substantially larger than their half-lives in the absence of poly(U). The condensation of 2′(3′)-O-(glycyl)-adenosine yields 5% of 5′-O-(glycyl)-adenosine in the presence of poly(U) compared to 0.7% in the absence of poly(U).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01732065
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  • 6
    Electronic Resource
    Electronic Resource
    Reasons for the occurrence of the twenty coded protein amino acids (1981)
    Springer
    Journal of molecular evolution 17 (1981), S. 273-284 
    Details
    ISSN: 1432-1432
    Keywords: Amino acids ; Molecular evolution ; Genetic Code ; Protein synthesis ; Prebiotic synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Factors involved in the selection of the 20 protein L-α-amino acids during chemical evolution and the early stages of Darwinian evolution are discussed. The selection is considered on the basis of the availability in the primitive ocean, function in proteins, the stability of the amino acid and its peptides, stability to racemization, and stability on the transfer RNA. We conclude that aspartic acid, glutamic acid, arginine, lysine, serine and possibly threonine are the best choices for acidic, basic and hydroxy amino acids. The hydrophobic amino acids are reasonable choices, except for the puzzling absences ofα-amino-n-butyric acid, norvaline and norleucine. The choices of the sulfur and aromatic amino acids seem reasonable, but are not compelling. Asparagine and glutamine are apparently not primitive. If life were to arise on another planet, we would expect that the catalysts would be poly-α-amino acids and that about 75% of the amino acids would be the same as on the earth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01795749
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  • 7
    Electronic Resource
    Electronic Resource
    Formation of pyrophosphate, tripolyphosphate, and phosphorylimidazole with the thioester, N, S-diacetylcysteamine, as the condensing agent (1981)
    Springer
    Journal of molecular evolution 18 (1981), S. 24-29 
    Details
    ISSN: 1432-1432
    Keywords: Thioester ; Pyrophosphate ; Tripolyphosphate ; Phosphorylimidazole ; Molecular evolution ; Prebiotic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Reaction of 0.20M orthophosphate with 0.20M N,S-diacetylcysteamine in 0.40M imidazole at pH 7.0 or 8.0 under drying conditions at 50°C for 6 days yields pyrophosphate and tripolyphosphate in the presence and absence of 0.10M divalent metal ion. The efficiency of utilization of N,S-diacetylcysteamine in the formation of pyrophosphate linkages ranges from 3 – 8% under the above conditions. The thioester, N,S-diacetylcysteamine, and imidazole are required for phosphoanhydride formation. Reaction of 0.40M orthophosphate with 0.20M N, S-diacetylcysteamine in 0.40M imidazole at ambient temperature for 6 days yields phosphorylimidazole in the absence or presence of 0.05M MgCl2. Phosphorylimidazole and pyrophosphate are formed in the presence of 0.05M CaCl2; pyrophosphate and tripolyphosphate are formed with 0.15M CaCl2. The efficiency of utilization of N,S-diacetylcysteamine in the formation of pyrophosphate linkages is roughly 7% at 6 days of reaction with 0.15M CaCl2. The thioester, N,S-diacetylcysteamine and imidazole are required for the formation of phosphoanhydrides. The significance of these reactions to molecular evolution is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01733208
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  • 8
    Electronic Resource
    Electronic Resource
    Alanine synthesis from glyceraldehyde and ammonium ion in aqueous solution (1985)
    Springer
    Journal of molecular evolution 21 (1985), S. 351-355 
    Details
    ISSN: 1432-1432
    Keywords: Alanine ; Amino acid ; Glyceraldehyde ; Thioester ; Intramolecular rearrangement ; Molecular evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Alanine is formed under anaerobic conditions from glyceraldehyde and ammonium ion in aqueous solutions of sodium phosphate (pH 7.0) or imidazole-imidazolium chloride (pH 7.0) at ambient temperature. In 500 mM imidazole (pH 7.0), alanine synthesis from 10 mM glyceraldehyde and 15 mM ammonium ion is roughly 6 times more rapid in the presence of 10 mM 3-mercaptopropionate (0.62% yield at 60 days) than in its absence (0.10% yield at 60 days). Likewise, the formation of alanine in 500 mM sodium phosphate (pH 7.0) from 5 mM glyceraldehyde and 10 mM ammonium ion is more rapid in the presence of 10 mM N-acetylcysteine than in its absence. In this reaction with N-acetylcysteine, the ratio of the yield of alanine to the yield of lactate is fairly constant. The yield of alanine is about 4.5% that of lactate. Alanine synthesis in the presence of thiol probably proceeds via alanyl thioester, which is produced by rearrangement of the imine of the hemithioacetal of pyruvaldehyde, a product of glyceraldehyde dehydration. The significance of this reaction for molecular evolution is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02115654
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  • 9
    Electronic Resource
    Electronic Resource
    Prebiotic sugar synthesis: Hexose and hydroxy acid synthesis from glyceraldehyde catalyzed by iron(III) hydroxide oxide (1992)
    Springer
    Journal of molecular evolution 35 (1992), S. 1-6 
    Details
    ISSN: 1432-1432
    Keywords: Sugar synthesis ; Glyceraldehyde ; Iron(III) hydroxide oxide ; Catalysis ; Aldol condensation ; Prebiotic ; Molecular evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Iron(III) hydroxide oxide [Fe(OH)O] efficiently catalyzed the condensation of 25 MM dl-glyceraldehyde to ketohexoses at 25°C (pH 5–6). At 16 days the yields were sorbose (15.2%), fructose (12.9%), psicose (6.1%), tagatose (5.6%), and dendroketose (2.5%) with 19.6% of triose unreacted. Analysis at 96 days showed no decomposition of hexoses. Under these conditions Fe(OH)O also catalyzed the isomerization and rearrangement of glyceraldehyde to dihydroxyacetone and lactic acid, respectively. In these reactions, about 10% of the glyceraldehyde was oxidized to glyceric acid with concurrent reduction of the iron(III) to iron(II). The partial reduction of Fe(OH)O did not noticeably reduce its ability to catalyze hexose synthesis. The relationship of these results to prebiotic sugar synthesis is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160255
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  • 10
    Electronic Resource
    Electronic Resource
    The formation of dipeptides from amino acids and the 2′(3′)-glycyl ester of an adenylate (1979)
    Springer
    Journal of molecular evolution 13 (1979), S. 185-191 
    Details
    ISSN: 1432-1432
    Keywords: Aminolysis ; Peptides ; t-RNA ; Amino acid esters ; Amino-acylnucleotides ; Molecular evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The yields of dipeptide obtained from the reaction of 0.2M 2′(3′)-O-(glycyl)-adenosine-5′-(O-methylphosphate) and 0.2M amino acid at pH 8.2 ranged from 0.1% to 35.5% for a group of 15 amino acids. The yields of glyser (35.3%), gly-cys (11.8%) and gly-thr (5.4%) were considerably greater than dipeptide yields obtained from any of the other 12 amino acids (≦ 1.7%). Aminolysis of 0.05M 2′(3′)-O-(glycyl)-adenosine-5′-(O-methylphosphate) by 0.4M serine ethyl ester yielded 53% glycylserine diketopiperazine, via N-(glycyl)-serine ethyl ester as a transient intermediate. The prebiotic significance of these reactions is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01739478
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