Formamide-based prebiotic chemistry

Current lifeforms on Earth are essentially composed of four classes of macromolecular entities: nucleic acids, proteins, carbohydrates, and lipids. Nucleic acids (DNA and RNA) embody and express the genetic information and, together, constitute the genome and the apparatus for its expression (the genotype). Proteins, carbohydrates, and lipids form structures which harness and handle energy from the environment for organizing matter according to the instructions specified by the genotype, aiming to its conservation and transmission. The ensemble of proteins, carbohydrates, lipids, and nucleic acids constitute the phenotype. Life is thus made of the interaction of metabolism and genetics, of the genotype with the phenotype. Both are built around the chemistry of the most common elements in the universe (hydrogen, oxygen, nitrogen, and carbon), with important although ancillary roles being played by phosphorus, sulphur, and a few other elements. Given the overwhelming variety of the chemically conceivable molecules, the fact that in biological systems we observe only a small subset of all possible organic molecules has raised questions about how and which different reaction pathways could have plausibly led to the synthesis of pre-biological molecules on the primordial Earth. These are the main objectives of prebiotic chemistry research. ==Precursor of biogenic molecules==

, cytosine, and 4(3H)pyrimidinone) in good yields was reported in 2001. These products were obtained by heating formamide in the presence of simple catalysts such as calcium carbonate (CaCO3), silica (SiO2), or alumina (Al2O3). In addition to nucleobases, sugars, carboxylic acids, amino acids, clays, cosmic dust analogues, phosphates, iron sulphide minerals, zirconium minerals, borate minerals, and numerous materials of meteoritic origin or slow protons and meteorites in aqueous environments. It has been suggested that the stepwise decrease of the temperature of the prebiotic environment could induce a sequence of strongly non-equilibrium chemical events that led to the emergence of more and more complex species from formamide on the early Earth. For each studied combination of catalyst/energy source/environment, formamide condensed into a variety of different prebiotically relevant compounds, each combination giving rise to a specific set of relatively complex molecules, usually encompassing several nucleobases, amino acids, and carboxylic acids. polymerization of 3’,5’ cyclic nucleotides, leading to the abiotic synthesis of RNA oligomers. This is the reason why formamide is considered a plausible medium for prebiotic phosphorylation reactions also in the “discontinuous synthesis” scenario of the origin of life. As well as phosphorylation, formamide has been shown to be a competent medium for the production of amino acid derivatives from their simple aldehyde and nitrile precursors, demonstrating that water is not the only solvent in which this process can occur. Most notably, formamide provides a medium for the prebiotic synthesis of cysteine derivatives, which was not previously considered plausible in strictly aqueous prebiotic environments. ==References==