eripituisin

Eripituisin is a cyclic peptide natural product isolated from marine cyanobacteria. It is classified as a ribosomally produced and post-translationally modified peptide (RiPP) and is notable for its unusual heterocyclic modifications that enhance stability.

The compound was first reported in 2012 by researchers surveying cyanobacterial extracts from coral reef habitats around Palau. The name reflects its marine origin and the distinctive character of the compound.

The mature molecule comprises a macrocycle formed from a deca- to dodecapeptide sequence bearing two thiazole rings and several nonproteinogenic amino acids. The macrocycle and modifications yield a rigid conformation that contributes to stability in aqueous environments.

In vitro studies show antifungal activity against Candida species and Aspergillus at low micromolar concentrations; antibacterial activity is weaker; cytotoxicity to mammalian cells at high concentrations is limited.

Production is linked to a gene cluster encoding a precursor peptide and tailoring enzymes including heterocyclases, oxidases, and a macrocyclization enzyme typical of RiPP pathways. Genetic studies indicate horizontal transfer across cyanobacterial lineages, suggesting a distributed biosynthetic potential among marine microbes.

Eripituisin is of interest as a model system for studying RiPP biosynthesis in marine organisms and as a potential starting point for antifungal drug development. No clinical applications have been approved, and research continues to characterize its biosynthesis, structure–activity relationships, and ecological role.