20-Residue and 11-residue peptaibols from the fungus Trichoderma longibrachiatum are synergistic in forming Na+/K+-permeable channels and adverse action towards mammalian cells

Raimo Mikkola, Maria A. Andersson, Laszlo Kredics, Pavel A. Grigoriev, Nina Sundell, Mirja S. Salkinoja-Salonen*

*Tämän työn vastaava kirjoittaja

Tutkimustuotos: LehtiartikkeliArticleScientificvertaisarvioitu


Certain species of the filamentous fungal genus Trichoderma (e.g. Trichoderma longibrachiatum and Trichoderma citrinoviride) are among the emerging clinical pathogens and also the most common species in the indoor space of mould-damaged buildings. The molecules involved in its pathology are not known. In the present study, we report that 0.52.6 wt% of the T. longibrachiatum mycelial biomass consisted of thermostable secondary metabolites mitochondriotoxic to mammalian cells. These were identified by LC/MS as one 11-residue and eight 20-residue peptaibols, AcAib-Asn-Leu/Ile-Leu/Ile-Aib-Pro-Leu/Ile-Leu/Ile-Aib-Pro-Leuol/Ileol (1175 Da) and AcAib-Ala-Aib-Ala-Aib-Ala/Aib-Gln-Aib-Val/Iva-Aib-Gly-Leu/Ile-Aib-Pro-Val/Iva-Aib-Val/Iva/Aib-Gln/Glu-Gln-Pheol(19361965 Da) (Aib, alpha-aminoisobutyric acid; Ac, acetyl; Ileol, isoleucinol; Iva, isovaline; Leuol, leucinol; Pheol, phenylalaninol). The toxic effects on boar sperm cells depended on these peptaibols, named trilongins. The trilongins formed voltage dependent, Na+/K+ permeable channels in biomembranes. The permeability ratios for Na+ ions, relative to K+, of the 11-residue trilongin channel (0.95 : 1) and the 20-residue trilongin channel (0.8 : 1) were higher than those of alamethicin. The combined 11-residue and 20-residue trilongins generated channels that remained in an open state for a longer time than those formed by either one of the peptaibols alone. Corresponding synergy was observed in toxicokinetics. With 11-residue and 20-residue trilongins combined 1 : 2 w/w, an effective median concentration (EC50) of 0.6 mu g center dot mL(-1) was reached within 30 min, and the EC50 shifted down to 0.2 mu g center dot mL(-1) upon extended exposure. By contrast, with 11-residue or 20-residue trilonging separately in 30 min of exposure, the EC50 values were 15 and 3 mu g center dot mL(-1), respectively, and shifted down to 1.5 and 0.4 mu g center dot mL(-1) upon extended exposure. This is the first report on ion-channel forming peptaibols with synergistic toxicity from T. longibrachiatum strains isolated from clinical samples.

DOI - pysyväislinkit
TilaJulkaistu - marraskuuta 2012
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

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