Pentadecaibins I–V: 15-Residue Peptaibols Produced by a Marine-Derived <i>Trichoderma</i> sp. of the <i>Harzianum</i> Clade

Abstract

In the course of investigations on peptaibol chemodiversity from marine-derived <i>Trichoderma</i> spp., five new 15-residue peptaibols named pentadecaibins I-V (<b>1</b>-<b>5</b>) were isolated from the solid culture of the strain <i>Trichoderma</i> sp. MMS1255 belonging to the <i>T. harzianum</i> species complex. Phylogenetic analyses allowed precise positioning of the strain close to <i>T. lentiforme</i> lineage inside the <i>Harzianum</i> clade. Peptaibol sequences were elucidated on the basis of their MS/MS fragmentation and extensive 2D NMR experiments. Amino acid configurations were determined by Marfey's analyses. The pentadecaibins are based on the sequences Ac-Aib¹-Gly²-Ala³-Leu⁴-Aib/Iva⁵-Gln⁶-Aib/Iva⁷-Val/Leu⁸-Aib⁹-Ala¹⁰-Aib¹¹-Aib¹²-Aib¹³-Gln¹⁴-Pheol¹⁵. Characteristic of the pentadecaibin sequences is the lack of the Aib-Pro motif commonly present in peptaibols produced by <i>Trichoderma</i> spp. Genome sequencing of <i>Trichoderma</i> sp. MMS1255 allowed the detection of a 15-module NRPS-encoding gene closely associated with pentadecaibin biosynthesis. Pentadecaibins were assessed for their potential antiproliferative and antimicrobial activities.