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Leslie E Orgel

Publications and source records attributed to Leslie E Orgel.

8 recordsLinked to original sources
PubMed2006

Amino acid dependent formation of phosphate anhydrides in water mediated by carbonyl sulfide.

Carbonyl sulfide (COS), a component of volcanic gas emissions and interstellar gas clouds, is shown to be an efficient condensing agent in the context of phosphate chemistry in aqueous solutions. We report that high-energy aminoacyl-phosphate anhydrides and aminoacyl adenylates are generated in solutions containing amino acids, COS, and the corresponding phosphate molecule. We further show that the mixed anhydrides of amino acids and inorganic phosphate are phosphorylating agents, producing pyrophosphate in better than 30% yield in the presence of Ca2+ precipitates. The amino acid dependent activations of phosphate reported here, which occur in parallel with the production of peptides, suggest that these two reactions may have shared a common intermediate on the prebiotic Earth.

Amino Acids↗
PubMed2004

Prebiotic adenine revisited: eutectics and photochemistry.

Recent studies support an earlier suggestion that, if adenine was formed prebiotically on the primitive earth, eutectic freezing of hydrogen cyanide solutions is likely to have been important. Here we revisit the suggestion that the synthesis of adenine may have involved the photochemical conversion of the tetramer of hydrogen cyanide in eutectic solution to 4-amino-5-cyano-imidazole. This would make possible a reaction sequence that does not require the presence of free ammonia. It is further suggested that the reaction of cyanoacetylene with cyanate in eutectic solution to give cytosine might have proceeded in parallel with adenine synthesis.

Adenine↗
PubMed2003

Some consequences of the RNA world hypothesis.

It is now generally accepted that our familiar biological world was preceded by an RNA world in which ribosome-catalyzed, nucleic-acid coded protein synthesis played no part. If the RNA world was the first biological world there is little that one can learn from biochemistry about prebiotic chemistry, except that the formation and polymerization of nucleotides were once prebiotic processes. If the RNA world was not the first biological world, the above conclusion may not be justified, and one can speculate that the monomers of earlier genetic polymers might be recognizable as important biochemicals. This suggests that the construction of replicating polymers from simple, not necessarily standard, aminoacids should be explored.

Amino Acids↗
PubMed2002

Is cyanoacetylene prebiotic?

Cyanoacetylene is an earlier intermediate in a proposed prebiotic synthesis of cytosine, while cyanoacetaldehyde is a later intermediate. There is no scientific basis for the claim that cyanoacetaldehyde is more plausibly prebiotic than cyanoacetylene in this context.

Acetylene↗
PubMedDate not supplied

Prebiotic chemistry and the origin of the RNA world.

The demonstration that ribosomal peptide synthesis is a ribozyme-catalyzed reaction makes it almost certain that there was once an RNA World. The central problem for origin-of-life studies, therefore, is to understand how a protein-free RNA World became established on the primitive Earth. We first review the literature on the prebiotic synthesis of the nucleotides, the nonenzymatic synthesis and copying of polynucleotides, and the selection of ribozyme catalysts of a kind that might have facilitated polynucleotide replication. This leads to a brief outline of the Molecular Biologists' Dream, an optimistic scenario for the origin of the RNA World. In the second part of the review we point out the many unresolved problems presented by the Molecular Biologists' Dream. This in turn leads to a discussion of genetic systems simpler than RNA that might have "invented" RNA. Finally, we review studies of prebiotic membrane formation.

Catalysis↗