HOW THE FIRST BIOPOLYMERS COULD HAVE EVOLVED

In this work, we discuss a possible origin of the first biopolymers wi th stable unique structures. We suggest that at the prebiotic stage of evolution, long organic polymers had to be compact to avoid hydrolysi s and had to be soluble and thus must not be exceedingly hydrophobic. We present an algorithm that generates such sequences for model protei ns. The evolved sequences turn out to have a stable unique structure, into which they quickly fold. This result illustrates the idea that th e unique three-dimensional native structures of first biopolymers coul d have evolved as a side effect of nonspecific physicochemical factors acting at the prebiotic stage of evolution.