Autocatalytic synthesis of a tetranucleotide analogue

Abstract

As an approach to the study of the kind of chemical process that might have contributed to the origin of life, attempts have been made to develop purely chemical systems in which oligonucleotides self-replicate. Although performed oligonucleotides have been shown to facilitate the formation of their complements from activated mononucleotides, only a restricted range of oligomers are efficient templates and it will clearly be difficult to find a pair of complementary oligomers each of which will facilitate the formation of the other. Many of the difficulties facing the development of a self-replicating system could be overcome by using a pair of complementary substrate molecules that condense together more easily than ribonucleotides. It would also be helpful if each substrate molecule contained equal numbers of purine and pyrimidine bases as, otherwise, there is a tendency for purines to be overrepresented in the products. We have therefore explored the chemistry of 3'-amino-3'-deoxynucleotides and their dimers. We report here that the tetranucleoside triphosphoramidate GNHpCNHpGNHpCN3 acts as a template to catalyse the condensation of GNHpCNH2 and pGNHpCN3, forming further molecules of the template. The system is therefore autocatalytic, and in accordance with elementary theory the amount of product made increases with the square root of the template concentration.

Asymmetric Autocatalysis and Its Implications for the Origin of Homochirality

“…The ''minimal systems'' for self-replication developed by von Kiedrowski (37,38) and others for nucleic acids (39), peptides (40,41), small organic molecules (42), and ribozymes (43) all represent autocatalytic systems based on core templates larger than those in the Soai reactions. However, none of those systems involve prochiral molecules, meaning that the origin of the first imbalance in asymmetric centers is not at issue in these cases; when we examine von Kiedrowski's (37,38) autocatalytic system based on DNA hexamers, for example, we know we are already firmly committed and residing in the camp of the L-amino acids and the D-sugars.…”

The origin of replicators and reproducers

“…But what kind of molecular mechanism could underlie such an odd type of growth? von Kiedrowski (1986) and Zielinski & Orgel (1987) were the first to show that oligonucleotide analogues follow a squareroot growth law in the appropriate medium. The reason, in a simplified form, is as follows.…”

RETRACTED: Replication of an RNA ligase ribozyme under alternating temperature condition

“…These reactions proceed in an autocatalytic manner if the new copies of T can direct the joining of A and B. The autocatalytic replication of the template molecule has been demonstrated for activated oligonucleotides [2][3][4], peptides [5,6], and small organic compounds [7][8][9].…”

“…Chemistry-based non-biological systems of the form A + B fi T has been proposed, where A and B are substrates that bind to a complementary template T and become joined to form a new copy of T [2]. These reactions proceed in an autocatalytic manner if the new copies of T can direct the joining of A and B.…”