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Trichorzins HA and MA, antibiotic peptides from Trichoderma harzianum. I. Fermentation, isolation and biological
C Goulard1, S Hlimi, S Rebuffat
1Laboratoire de Chimie des Substances Naturelles, URA 401 CNRS, Museúm National d'Histoire Naturelle, Paris, France.
Abstract:
Trichorzins HA and MA, original 18-residue peptides, were isolated from two strains of the widespread soil fungus Trichoderma harzianum which have been shown to exhibit antibiotic activity against phytopathogenic fungi. These linear peptides belonging to the peptaibol class are biosynthesized as a complex of closely related analogues. Nine major pure peptides, six trichorzins HA and three trichorzins MA, were isolated by reversed-phase HPLC. The isolated peptides exhibited antibacterial activity against S. aureus and increased the membrane permeability of egg phosphatidylcholine/cholesterol (7/3) liposomes, as measured by monitoring leakage kinetics of a fluorescent probe. Structure-activity relationships were deduced from the antibiotic and membrane-modifying properties.
Insights
Trichoderma harzianum produces trichorzins, peptides with antibacterial activity against Staphylococcus aureus. These peptaibols also increase the permeability of liposomes, suggesting potential antimicrobial applications.
Area of Science:
- Microbiology
- Biochemistry
- Peptide Science
Background:
- Trichoderma harzianum is a soil fungus known for its antibiotic properties against plant pathogens.
- Peptaibols are a class of linear peptides with antimicrobial activity.
- Trichorzins are a specific group of peptaibols produced by T. harzianum.
Purpose of the Study:
- To isolate and characterize trichorzins HA and MA from T. harzianum.
- To investigate the antibacterial and membrane-modifying activities of these peptides.
- To establish structure-activity relationships for trichorzins.
Main Methods:
- Isolation of nine major pure peptides (six trichorzins HA, three trichorzins MA) using reversed-phase High-Performance Liquid Chromatography (HPLC).
- Assay of antibacterial activity against Staphylococcus aureus.
- Measurement of liposome membrane permeability using a fluorescent probe leakage assay.
Main Results:
- Isolated trichorzins HA and MA demonstrated antibacterial activity against S. aureus.
- The peptides increased membrane permeability in egg phosphatidylcholine/cholesterol liposomes.
- Structure-activity relationships were elucidated based on observed biological activities.
Conclusions:
- Trichorzins from T. harzianum possess significant antibacterial properties.
- These peptaibols exhibit membrane-disrupting capabilities.
- The findings provide insights into the antimicrobial mechanisms and potential applications of trichorzins.