The most important tasks in the molecular processes of living organisms are performed by highly modular, strand-like molecules - biopolymers - made up of sequences of a small number of elementary units (4 nucleotide bases for DNA, 20 amino acids for proteins). Molecular recognition, catalysis, transport, information storage and duplication, energy conversion and storage, motors - these functions rely on the ability of biopolymers to adopt folded, three-dimensional structures defined by the sequence of the monomers of which they are composed. Until about fifteen years ago, folding ability was considered the exclusive prerogative of biopolymers. However, a major paradigm shift has resulted from important discoveries in chemistry. Numerous non-natural oligomers and polymers have been synthesized and have also demonstrated folding ability. In fact, biopolymers are just a few of the many families of molecules capable of folding. Some of these artificial folded structures, known as "foldamers", are close to biopolymers and have applications as mimics of the biological structures they resemble: they are known, for example, as peptidomimetics or nucleomimetics. Other foldamers are structurally distant from biopolymers and offer the prospect of structures and functions beyond those produced by nature. The interest in studying foldamers therefore lies primarily in their differences from biopolymers, not in their similarity: what can different chemical compositions offer that's new?
Our team has developed an original family of foldamers based on aromatic amino acids. Sequences of aromatic amino acids possess certain characteristics of nucleic acids (aromatic stacking in folded structures) and certain characteristics of peptides and proteins (polyamide skeleton). These foldamers adopt helical structures, some of which possess unprecedented conformational stability, providing robust building blocks for the development of very large synthetic folded architectures.
