Oligonucleotides, prebiotic synthesis

Palchetti I, Mascini M (2005) Electrochemical Adsorption Technique for Immobilization of Single-Stranded Oligonucleotides onto Carbon Screen-Printed Electrodes. 261 27-43 Pascal R, Boiteau L, Commeyras A (2005) From the Prebiotic Synthesis of a-Amino Acids Towards a Primitive Translation Apparatus for the Synthesis of Peptides. 259 69-122 Paulo A, see Santos I (2005) 252 45-84 Perez EM, see Leigh DA (2006) 265 185-208 Perret F, see Coleman AW (2007) 277 31-88 Perron H, see Coleman AW (2007) 277 31-88 Pianowski Z, see Winssinger N (2007) 278 311-342 Piestert F, see Gansauer A (2007) 279 25-52... 

Saladino R, Crestini C, Costanzo G, DiMauro E (2005) On the Prebiotic Synthesis of Nucle-obases, Nucleotides, Oligonucleotides, Pre-RNA and Pre-DNA Molecules. 259 29-68 Santos I, Paulo A, Correia JDG (2005) Rhenium and Technetium Complexes Anchored by Phosphines and Scorpionates for Radiopharmaceutical Applications. 252 45-84 Santos M, see Szathmdry E (2005) 259 167-211... 

I believe that the bottom-up approach to the origin of life will enjoy a considerable boost, when conditions are found for the prebiotic synthesis of many identical copies of long (>30) co-oligopeptide or co-oligonucleotide sequences. This would at least show that the prebiotic synthesis of enzymes and/or RNA is in principle possible. This remains the main problem with the prebiotic RNA world. 

On the Prebiotic Synthesis of Nudeobases, Nucleotides, Oligonucleotides, Pre-RNA and Pre-DNA Molecules... 

Keywords Origin of life Prebiotic synthesis Nucleic bases Nucleotides Oligonucleotides... 

Saladino R, Crestini C, Costanzo G, DiMauro E. On the prebiotic synthesis of nucleo-bases, nucleotides, oligonucleotides, pre-RNA and pre-DNA molecules. Top Curr Chem 2005 259 29-68. 

A new method for forming 2, 3 -cyclic phosphates of ribonucleosides using very mild conditions has been described. It may also be used to introduce a terminal cyclic phosphate in protected oligonucleotides. When 2, 3 -cyclic AMP is evaporated from solution at alktiline pH in the presence of aliphatic diamines, and maintained dry at elevated temperatures, polymerization occurs. Oligomers up to the hexanucleotide are formed, preferentially with 3 ->5 internucleotidic links. This may have been an important process in prebiotic synthesis. 

One of the most elegant applications of DCC is the extensive and now classic synthesis of oligonucleotides by H. G. Khorana and his coworkers. Because of the primordial nature of deoxyribonucleic acids, I undertook with the collaboration of J. Ibanez and other coworkers the prebiotic synthesis of oligodeoxyribonucleotides. For reasons of simplicity, we selected the synthesis of oligothymidylic acid as a model. 

A further unusual feature of the matrix-dependent polycondensation lies in the character of the nucleobases themselves. Purine mononucleotides undergo polycondensation, in good yields, at complementary matrices consisting of pyrimidine polymers. However, the synthesis of pyrimidine oligonucleotides from their mononucleotides at purine matrices is not effective. This important fact means that a pyrimidine-rich matrix leads to a purine-rich nucleic acid, which is itself not suitable to act as a matrix. This phenomenon also occurs when matrices are used which contain both basic species, i.e., purines and pyrimidines. An increase in the amount of purine in a matrix leads to a clear decrease in its effectiveness (Inoue and Orgel, 1983). However, the authors note self-critically that the condensation agent used cannot be considered to be prebiotic in nature. 

Although the pre-RNA world is now much more the centre of scientific attention in prebiotic chemistry, there have been several attempts in recent years to understand the synthesis of oligonucleotides from the normal nucleotides by using simulation experiments (Ferris, 1998). In condensation reactions in aqueous media, there is always competition between synthesis and hydrolysis synthesis is generally only successful when supported by catalysts. 

Compelling—though indirect—evidence for this view comes from model studies of possible prebiotic template-directed oligonucleotide synthesis. In these experiments, a single-stranded homopurine or homopyrimidine polynucleotide is used as a template, and the ability of the prebiotic system to achieve synthesis of the complementary strand from mononucleotide precursors is measured. Since there is no polymerase present, the success of the system depends on the ability of the mononu-... 

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