Fungisporin
Fungisporin is a antibiotic with the molecular formula C28H36N4O4 which is produced by Aspergillus and Penicillium species. The cyclic peptide is a tetramer, consists of one each of the two enantiomeric forms of phenylalanine and of valine. References

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Fusarium
Cyclic peptides
Tetrapeptides
Twelve-membered rings