Chemical evolution of RNA under hydrothermal conditions and the role of thermal copolymers of amino acids for the prebiotic degradation and formation of RNA

Kawamura, Kunio; Nagahama, Minoru; Kuranoue, Kazuhiro

doi:10.1016/j.asr.2005.04.071

Cited by 11 publications

(10 citation statements)

References 44 publications

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“…Besides, the increase of the ImpC hydrolysis with increasing temperature is a main reason of the low yield of oligo(C) at high temperatures in the present reaction system. These facts suggest that the formation of oligonucleotides would be possible if the relative reaction rate of 2-mer formation is enhanced in the TD reaction and the hydrolysis of the activated nucleotide monomer is inhibited in the present system by some additives, such as protein-like molecules and minerals (Kawamura 2005;Kawamura et al 2005). We are currently searching such materials as well as continuing kinetic analyses of temperature dependence of other prebiotic models of the oligonucleotide formation.…”

Section: Temperature Dependence Of the Rate Constants And The Chemicamentioning

confidence: 89%

Kinetic Analysis of Oligo(C) Formation from the 5′-Monophosphorimidazolide of Cytidine with Pb(II) Ion Catalyst at 10–75°C

Kawamura

Maeda

2007

Orig Life Evol Biosph

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The temperature dependence of the rate constants for the formation of oligocytidylate (oligo(C)) from the 5'-monophosphorimidazolide of cytidine (ImpC) in the presence of Pb(II) ion catalyst has been investigated at 10-75 degrees C. The rate constants for the formation of oligo(C) increased in the order of the formation of 2-mer < 3-mer < or = 4-mer; this trend resembles the trend in the cases of the template-directed and the clay-catalyzed formations of oligonucleotides. While the rate constants of the formation of oligo(C) increased with increasing temperature, the yield of oligo(C) decreased with increasing temperature. This is due to the fact that the relative magnitude of the rate constants of the formation of 2-mer, 3-mer, and 4-mer to that of the hydrolysis of ImpC decreased with increasing temperature. This is probably due to the fact that association between ImpC with the elongating oligo(C) decreases with increasing temperature. The apparent activation energy was 61.9 +/- 8.5 kJ mol(-1) for the formation of 2-mer, 49.3 +/- 2.9 kJ mol(-1) for 3-mer, 51.8 kJ mol(-1) for 4-mer, and 66.8 +/- 4.5 kJ mol(-1) for the hydrolysis of ImpC. The significance of the temperature dependence of the formation rate constants of the model prebiotic formation of RNA is discussed.

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Section: Temperature Dependence Of the Rate Constants And The Chemicamentioning

confidence: 89%

Kinetic Analysis of Oligo(C) Formation from the 5′-Monophosphorimidazolide of Cytidine with Pb(II) Ion Catalyst at 10–75°C

Kawamura

Maeda

2007

Orig Life Evol Biosph

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“…The possible pathways by which oligopeptides and protein-like molecules were formed in prebiotic conditions have been widely proposed through a number of experiments simulating conditions on primitive Earth [19-21, 47, 48]; such protein-like molecules have been found to possess several enzymatic activities [48]. In addition, ribonuclease activity has also been observed in short peptides [49,50] and prebiotic protein-like molecules, which are randomly formed by thermal condensation of amino acid mixtures [40]. However, the RNase activity of such prebiotic protein-like molecules is at least 37000 times weaker than the activity of RNase A [40].…”

Section: Stability Of Rnase a In Relation To The Origin-of-life Problemmentioning

confidence: 99%

“…The sample solutions containing HT-RNase were stored at -18°C until analysis. The degradation of poly(U) was analyzed by AE-HPLC [39,40].…”

Section: Degradation Of Rnase Amentioning

confidence: 99%

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Stability of ribonuclease A under hydrothermal conditions in relation to the origin-of-life hypothesis: verification with the hydrothermal micro-flow reactor system

2009

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The stability of ribonuclease A (RNase A) was quantitatively investigated with the hydrothermal micro-flow reactor system (HFRS) at temperatures of up to 275°C from the viewpoint of the hydrothermal origin-of-life hypothesis. The enzymatic activity of RNase A was studied with regard to the catalytic degradation of polynucleotides with anion-exchange high-performance liquid chromatography, while the degradation of RNase A to shorter molecules was analyzed by size exclusion chromatography (SEC) and mass spectrometry (MS). The degradation of RNase A started within 10 s at 200°C, and the enzymatic activity disappeared almost completely after 25 s. SEC and MS analyses indicated that RNase A was thermally degraded to 2 large fragments, which, along with RNase A, were further decomposed to smaller fragments. This study showed that RNase A is fairly stable under normal conditions, but its enzymatic activity disappears rapidly at extremely high temperatures. The half life of RNase A and its fragments under hydrothermal conditions is comparable to or longer than the enzymatic reaction time scale of modern enzymes. Furthermore, this study demonstrates that HFRS is reliable and useful for verifying the stability of several proteins in fundamental and applied research as well as for studying the origin-of-life problem.

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“…However, an equally plausible interpretation is that the fundamental biochemistry of P i -based life emerged in an As-rich environment. [35][36][37][38][39] . It is therefore plausible that As-based life emerged in As-rich environments and, once established, evolved strategies that would enable it to persist there.…”

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confidence: 99%

Did nature also choose arsenic?

Wolfe-Simon

Davies

Anbar

2009

International Journal of Astrobiology

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All known life requires phosphorus (P) in the form of inorganic phosphate (PO43−or Pi) and phosphate-containing organic molecules. Piserves as the backbone of the nucleic acids that constitute genetic material and as the major repository of chemical energy for metabolism in polyphosphate bonds. Arsenic (As) lies directly below P on the periodic table and so the two elements share many chemical properties, although their chemistries are sufficiently dissimilar that As cannot directly replace P in modern biochemistry. Arsenic is toxic because As and P are similar enough that organisms attempt this substitution. We hypothesize that ancient biochemical systems, analogous to but distinct from those known today, could have utilized arsenate in the equivalent biological role as phosphate. Organisms utilizing such ‘weird life’ biochemical pathways may have supported a ‘shadow biosphere’ at the time of the origin and early evolution of life on Earth or on other planets. Such organisms may even persist on Earth today, undetected, in unusual niches.

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Chemical evolution of RNA under hydrothermal conditions and the role of thermal copolymers of amino acids for the prebiotic degradation and formation of RNA

Cited by 11 publications

References 44 publications

Kinetic Analysis of Oligo(C) Formation from the 5′-Monophosphorimidazolide of Cytidine with Pb(II) Ion Catalyst at 10–75°C

Kinetic Analysis of Oligo(C) Formation from the 5′-Monophosphorimidazolide of Cytidine with Pb(II) Ion Catalyst at 10–75°C

Stability of ribonuclease A under hydrothermal conditions in relation to the origin-of-life hypothesis: verification with the hydrothermal micro-flow reactor system

Did nature also choose arsenic?

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