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RESEARCH PRODUCT

Methods for the rapid detection, isolation and sequence determination of “peptaibols” and other aib-containing peptides of fungal origin. I. Gliodeliquescin a fromGliocladium deliquescens

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A rapid and simple detection procedure of Aib-containing “peptaibol” polypeptide antibiotics (mycotoxins) in fungal culture broths is described which employs alkylsilica (Sep-Pak®) cartridges for a selective enrichment, and the utilization of the unusualα-aminoisobutyric acid (Aib) and amino alcohols as specific marker constituents, which are easily detectable in total hydrolysates. Preparative isolations from fermentation broths is facilitated by adsorber resin (XAD) column chromatography, and purification of crude isolates is achieved by silica gel- and sephadex LH-20 chromatography. Preparative HPLC using spherical, totally porous ODS-bonded phases enables the isolation of uniform peptides, completely free of sequence analogs, from microheterogeneous peptaibol mixtures, and analytical HPLC of highest resolution allows a “fingerprint” assignment of microheterogeneous peptaibols of different fungal origin. Fast atom bombardment mass spectrometry is demonstrated to be a rapid and precise method for the complete sequence determination of peptaibols when employing sophisticated liquid matrix systems including both, lipophilic tetraethylenglycol and hydrophilic glycerol combined with a selective, trifluoroacetolytic cleavage step carried out directly “on target” (in situ). The versatility of the methods described is demonstrated with the detection and sequence determination of the new membrane-altering eicosapeptide named gliodeliquescin A from the soil fungusGliocladium deliquescens NRRL 3091 establishing the occurence of peptaibols in that fungal genus for the first time.