A model for the role of short self-assembled peptides in the very early stages of the origin of life.

The molecular basis of the origin of life is one of the most fundamental questions in modern biology. While the "RNA world" hypothesis offers a very sensible model for the evolvement of the current biochemical networks, there is a lack of knowledge about the early steps that led to the formation of the first RNA molecules. This issue is essential as it is practically impossible that complex molecules as functional RNA oligonucleotides had evolved spontaneously. It was recently demonstrated that peptide molecules as simple as dipeptides can self-assemble into well-ordered tubular, fibrilar, and closed-cage structures. Other studies have confirmed the ability of dipeptides to act as catalysts and the capability of other peptides, as short as tripeptides, to serve as a template for nucleotide binding and orientation. Unlike complex RNA molecules, the spontaneous formation of functional short peptides in the primordial earth conditions is very likely. We suggest a novel mechanism for the origin of life that is based on the ability of short peptides to form encapsulated structures, catalyst chemical reaction, and serve as highly ordered template for the assembly of nucleotides. This model may explain the early events that led to the formation of the current biochemical machinery that combines the elaborated and coordinated interaction between nucleic acids and proteins to allow the function of living systems.