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Proceedings of the 31 st European Peptide SymposiumMichal Lebl, Morten Meldal, Knud J. Jensen, Thomas Hoeg-Jensen (Editors)European Peptide Society, 2010Sequences of the Polypeptide Antibiotics (Peptaibiotics)AcretocinsHans Brückner and Jochen KirschbaumResearch Center for BioSystems, Land Use and Nutrition (IFZ), Departmentof Food Sciences, University of Giessen, Giessen, 35392, GermanyIntroductionPeptaibiotics are a constantly growing family of fungal peptides characterized by a highproportion of the α-dialkylated α-amino acid Aib (α-aminoisobutryric acid,2-methylalanine). They display a multitude of biological activities. We have developedrapid and reliable methods to screen fungi for the production of peptaibiotics which arebased on the detection of the marker amino acid Aib by GC-MS or HPLC. Solid-phaseextraction of peptides and subsequent online LC-ESI-MS n (‘peptaibiomics’) are used todetermine the entirety of peptaibiotics (the ‘peptaibiome’) [1-3]. We have already reportedon the production and sequences of a mixture of 16-residue peptaibiotics named acretocins(ACRs) by Acremonium crotocinigenum CBS 217.70. However, at that time we could notassign a mass fragment of Δ142 Da (Gly + 83 Da) in MS/MS experiments [4]. Here, weshow that it represents the sequence Gly 8 -Acc 9 (Acc, 1-aminocyclopropane-1-carboxylicacid) present in all acretocin homologues.Results and DiscussionThe mold A. crotocinigenum CBS 217.70 [3] was grown in submerged culture using a maltextract medium. Acretocins (ACRs) were isolated and purified by XAD and LH-20chromatography as described previously [4]. The analytical HPLC elution profile of ACRsin comparison to the related peptaibiotics tolypin [5] and efrapeptin [6] are shown inFigure 1. The peptide mixture was fractioned by semi-preparative RP-HPLC, and theindividual peptides were analyzed by direct infusion ESI-MS and online HPLC-ESI-MS n .An aliquot of ACRs (0.2 mg) was hydrolyzed in 6M HCl (110°C/24 h). The amino acidsreleased were converted into their N-trifluoroacetyl-2-propyl esters. The derivatives wereanalyzed by GC-SIM-MS and GC-TIC-MS using a Chirasil-L-Val © capillary column. Thepresence of the previously undetected Acc (Figure 1) as well as other constituents wasdetermined.Fig. 1. HPLC elution profiles (left side) of acretocins [4] in comparison to tolypins [5] andefrapeptins [6]. GC-MS (right side) of TFA-amino acid-2-propyl esters of a totalhydrolysate of acretocins on Chirasil-L-Val; EI-MS of Acc from acretocins (insert above)and from a standard of Acc (insert below).386