Nodularines
Nodularines are a class of cyclic heptapeptide natural products originally isolated from the freshwater cyanobacterium Nodularia sp. These compounds belong to the nodularin family, which also includes nodularin R, nodularin Y, and nodularin A. Structurally, nodularines are characterized by a macrocyclic backbone composed of seven amino acid residues, including unusual amino acids such as β-(1-carboxyethyl)-L-isoaspartic acid and D-homoarginine. The cyclization typically occurs through an amide bond between the N-terminal and C-terminal residues, conferring high metabolic stability.
The primary biological activity of nodularines involves inhibition of protein phosphatases PP1 and PP2A, similar to
Environmental monitoring of freshwater bodies often detects nodularines due to cyanobacterial blooms. Their presence has prompted