Antimicrobial peptides are widespread in all living organisms, which have adapted to the constraints of their environment over the course of evolution. They are part of the immune heritage of metazoans. They are also competitive molecules for micro-organisms.

This axis, which forms the basis of the MuFoPAM network, is dedicated to exploring this diversity in terms of origin, structure and biological activity.

The diversity of antimicrobial peptides in living organisms provides a prolific source of natural peptides of interest. Their discovery is based in particular on the exploration of genomic and transcriptomic data, on the study of non-model organisms that have colonised little-studied habitats, and on the exploration of microbiota.

Antimicrobial peptides display an extraordinary diversity of structures (linear, cyclic, with or without disulphide bridges, etc.) and conformations (helix, leaflet, extended structure). In micro-organisms, their diversity is increased by the diversity of biosynthetic pathways: peptides of non-ribosomal or ribosomal origin, the latter being able to carry complex and varied post-translational modifications.

Design based on structure/activity relationships, the development of machine learning methods, bioengineering and the contribution of custom peptide synthesis are making it possible to generate new peptides or peptidomimetic derivatives with improved properties.

In addition to their antimicrobial activity, antimicrobial peptides have revealed a wide range of biological activities and are now considered to be multifunctional molecules.

At sub-inhibitory concentrations, they can act as chemical mediators involved in immunomodulation in metazoans or quorum sensing in micro-organisms.

In addition to this role in the physiology of the producer organism, some antimicrobial peptides have activities with a high potential for development: antiparasitic, antiviral, anticancer, etc.