New short peptaibols from a marine Trichoderma strain

Area of Science:

• Biochemistry
• Mass Spectrometry
• Mycology

Background:

• Peptaibols are bioactive peptides produced by fungi.
• Marine-derived microorganisms are a rich source of novel natural products.
• Trichoderma longibrachiatum is known to produce various secondary metabolites.

Purpose of the Study:

• To investigate the peptibol production of a marine-related Trichoderma longibrachiatum strain.
• To develop and apply a methodology for sequencing peptaibols directly from a mixture.
• To identify and characterize novel peptibol structures.

Main Methods:

• Electrospray ionisation multiple-stage ion trap mass spectrometry (ESI-MSn-IT) for structural analysis.
• Gas chromatography/electron impact mass spectrometry (GC/EI-MS) for complementary analysis.
• Methodology for sequencing short peptaibols (11 amino acids) in complex mixtures without prior separation.

Main Results:

• Two main groups of peptaibols were identified: long (20 amino acids) and short (11 amino acids).
• Nine peptaibols were identified in the mixture.
• Eight new peptaibols were discovered, including trichobrachin A I-IV and trichobrachin B I-IV, with novel amino acid sequences (Aib9-Pro10 and Val9-Pro10).

Conclusions:

• The study successfully identified and sequenced novel peptaibols from a marine-derived T. longibrachiatum.
• The developed methodology enables direct sequencing of peptaibols in mixtures, simplifying analysis.
• The discovery of new trichobrachins expands the known repertoire of fungal peptaibols and their structural diversity.