Possible Role of Ice in the Synthesis of Polymeric Compounds

Cellular life relies on a collection of linear polymers (among them DNA, RNA, proteins) to perform the functions necessary to its survival. It seems likely that catalytic and informational polymers played essential roles in the emergence of the first living entities, precursors of contemporary cells. Thus, their detection on other planetary bodies might hint at either emerging, or extant, or past life in these environments. A non-enzymatic synthesis of such polymeric materials or their precursors likely had to rely on a supply of monomers dissolved at low concentrations in an aqueous medium. An aqueous environment represents a clear hurdle to the synthesis of long polymers as it tends to inhibit polymerization due to entropic effects and favors the reverse reaction (decomposition by hydrolysis). It was therefore proposed that polymerization could occur in a distinct microor nanostructured environment that would permit a local increase in the monomer concentration, reduce water activity and protect monomers and polymers from hydrolysis. Several types of microor nanostructured environments, among them mineral surfaces [1], lattices of organic molecules, such as amphiphile bilayer structures [2], and the eutectic phase in water-ice [3, 4, add 2008 JIB, 2008 Chem. Biodiv] have been proposed to promote RNA NH