Harzianum A

Harzianum A is a trichothecene-type sesquiterpene produced by Trichoderma arundinaceum and related species. It consists of the 12,13-epoxytrichothec-9-ene core structure bearing a distinctive polyketide-derived octa-2,4,6-trienedioyl substituent esterified at C4. Biosynthetic studies identified the cytochrome P450 monooxygenase Tri23 as essential for formation of the acyl side chain. As a member of the trichothecene family, harzianum A inhibits eukaryotic protein synthesis by targeting the ribosomal peptidyl transferase center, a conserved mechanism characteristic of trichothecene toxins.